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Thread: SS Auto: Everything you ever wanted to know.

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    Default SS Auto: Everything you ever wanted to know.

    Well everyone,

    It may not actually be everything, but I figure that I should post information I've got on the SS Auto's here.

    If anyone of you that own a 5th Gen have an SS Auto, then you may be aware that Honda has finally decided to warranty 2000-2001 Prelude Auto Transmissions up to 100,000 miles.

    Of course, this means that the rest of us that have been bitching about the numerous failures we've been experiencing with our 1997-1999 Preludes are out of luck...

    Basically, SS Auto failures have historically fallen into two categories:

    1) Never had a problem.

    2) Transmission went very early on (usually under 30,000 miles), and possibly again afterwards.

    I've been following this issue for a number of years and have a fair amount of information. I'm going to post that info here for everyone:

    SS Auto Background:

    Honda used the Prelude as it's test bed for much of it's new technology. This was the case for the SS Auto 5th Gen and the 4 speed version of the transmission.

    Initially, Honda thought that the design would translate from paper to a decent product. Unfortunately, they ran into manufacturing problem - mostly quality control related due to the very tight tolerances in the transmission.

    When the first problems started to be reported, Honda let the local dealers attempt to fix the problem. Generally, this entailed sending the trans out to a local trans shop to repair the unit with Honda OEM parts. Unfortunately, the trans' design was a little too new and a lot more difficult to work on. The failure rate was almost 100% attempting this form of repair.

    So, Honda decided that they had to put a stop to dealers working on the transmissions. They immediately told the dealers that there was only one fix for an SS Auto: Let it completely fail and then replace it.

    It turns out that Honda's own remanufacturing division started to have problems as well. They started to see a 40% failure rate on the SS Autos from the Prelude.

    So, after a few years of horrible results, they turned to a company that was in the remanufacturing business. These guys were able to reliably rebuild the SS Autos and even offer a decent warranty.

    That same company recommended a few improvements in the SS Auto parts, and in 2000 Honda silently updated some of parts and changed the part numbers.

    The primary reason Honda has been so successful at ignoring Prelude owners and not dealing with the problem in a timely manner is that there are so few Honda Preludes with the SS Auto transmission. In a typical year Honda sold about 10,000 Preludes (5th Gen), and maybe 40 percent of those sales were SS Autos (4000 cars a year times 5 years of production = 20,000 car total!).

    They would never be able to get away with this with a Honda Accord, which sells about 450,000 cars a year. So any problems would be reported by the masses to the NTSA and possibly risk a recall. (Hence the reason the SS Auto extended warranties began...Someone with a Acura TL was almost killed.)

    Like many large companies: Honda seems to like to screw the little guy. Unfortunately, it is more likely that someone will have to die in an accident related a sudden transmission failure before Honda will take care of all SS Auto vehicle owners. They simply don't want to pay for a recall and consider good faith as nothing but lip service.

    Replacement Options:

    As of this moment, there are two companies that appear to rebuild the SS Auto. The first company, Howard Engineering, has been doing so since the beginning of the problems. The second company has recently grown in name, is much less expensive, and offers a less lengthy warranty: Phoenix Remaned Transmission.
    In the future as other SS Auto Honda models become more prevalent it’s like there will be more reliable sources for rebuilds.

    Howard Engineering:

    If your transmission fails out of warranty, you should consider having the dealer contact Howard and get a remanufactured unit from them.

    They offer 5 year / 50,000 mile warranties.

    Honda only offers a 12 month / 18,000 mile warranty on their replacement units.

    With Howard, they will also pay for the removal and installation of the transmission if it should fail. In other words: Howard offers a dealer like warranty that costs you nothing out of pocket should the unit fail (and includes a rental car!).

    Phoenix Remanufactured Transmissions:

    These guys are a wholesale / retail distributor that sells bulk rebuilt transmissions. Interestingly, they seem to know a lot about Honda transmissions from late model vehicles. I've spoken with a guy from the company, Andre, and he indicated that there were initially a lot of problems with rebuilding the sequential sportshift type automatics. Around 2000 Honda created a change in the parts for the Prelude SS Auto to deal with inherent problems. He further indicated the retrofitted (rebuilt) transmissions really should be quite reliable, and that they rebuild a large number of Honda SS type trannies (including Acura).

    A quick search by one of the members of showed that they also have an eBay outlet. They've sold hundreds of transmissions via EBay Motors and have 660+ positive feedbacks and 2 negative! That's some what impressive.

    The other interesting thing about the guy on the phone was they he knew their company’s exact failure rate on all rebuilds and was willing to tell me: .13% of all of their transmissions fail. Their warranty is 6 months or 6000 miles. I guess they figure that if the transmission works from the beginning, then it should continue to work until normal wear and tear causes it to fail.

    Unlike the cost of the OEM or Howard Rebuilds (about $3700), you can get a rebuild from Phoenix for $1050.00. However, Prelude SS Auto transmissions are hard to find, so you may need to send them your SS Auto and T-Converter so that they can build it. (They may not have an SS Auto in stock.) This could take up to 10 days. (The same exact thing happens with the dealer as well: They take your tranny out and send it back to Honda for rebuild.)

    Their address is:

    Phoenix Remanufactured Transmissions
    7310 W. Roosevelt Suite 26
    Phoenix, AZ 85043

    In General with Rebuilds:

    Don't waste your time having a local shop rebuild your tranny, they'll just screw it up and you'll be without your car. (This has been the case in about 9 out of 10 stories that folks have reported to me using companies like AMMCO, Lee Myles, etc.)

    You need to use a company with a lot of experience rebuilding Honda SS Auto transmissions, otherwise you risk wasting your cash on an unproven quantity.
    A Note about American Honda:
    Many people have contacted me and told me about their problems with getting their Honda dealer to replace their SS Auto when it starts acting up (any of the symptoms listed in this note). Generally, the symptoms start minor and then get progressively worse. Usually, the tranny has issues it does not fail immediately. This means that Honda can tell you that there is nothing wrong with the transmission and then tell you to go away. I suspect the reasons for Honda ignoring the problems are two fold:
    First, Honda has only one repair procedure for most of the SS Auto tranny problems: Replacement with a Remanufactured Unit. So, what the dealer tends to do is tell you something like “All Hondas do that” in order to get you to go away until the transmission completely fails. Generally, they will not fix the problem until the issue is so bad that it can’t be ignored. Initial signs of failure are generally ignored by Honda dealers.
    Second, Honda dealers get paid a reduced rate for labor on warranty claims. So the dealers are generally not interested in doing warranty work when they’ve got plenty of regular work that they’ll get paid full price for.
    The problem with both of the above is that it is possible that you are ignored to the point that you vehicle is no longer under warranty. At which time you find yourself paying for a tranny job that is very expensive at the dealer, that very few other companies are capable of rebuilding properly, and that has been a problem while the car was under warranty. Remember to take the car to the dealer and complain as many times as it takes to establish a paper trail that can be used to force Honda to repair your tranny under warranty. Most states division of consumer affairs live for going after car manufacturers / dealers. Especially when you have the documentation proving that you’ve tried to take care of the problem.

    A Note about Level 10:

    Level 10 is a company that rebuilds transmission with “high performance” parts that supposedly “bullet proof” your transmission. Many SS Auto Prelude owners have tried using Level 10. Better results are generally found IF you are sending your COMPLETE transmission and t-converter assemblies to them! That being said, there are still a large number of failures when their kits are used to rebuild your transmission. The worst part is that they rarely honor their warranty. Be very specific with them and get everything in writing. This way you can go to small claims court and get some of your money back. Be a smart consumer, get it in writing. (Deliverables and Warranty)

    SS Auto Transmission Failure Symptoms:

    These are the problems most people report when their trannies are failing:

    1) Hard Shifts: A hard shift is when the transmission shifts from one gear to another, but BANGS itself into the next gear.

    2) Soft Shifts: A soft shift is when the transmission takes a long slide into the next gear. So rather than crisply shifting into the next gear over 1 to 3 seconds, the transmission sides into the next gear over 3 to 15 seconds.

    3) Slipping: Slipping is when the transmission either takes a long time to go into the next gear, or no longer goes into the next gear. When the unit attempts to shift to the next gear, the unit "slides" but doesn't quite get there. As a result the tachometer revs a few thousand RPM higher than it would normally, as there is no longer any load on the engine.

    4) Grinding: Grinding is something the does happen, but it's really not typical. It's self explanatory and a sign of catastrophic failure.

    Typical symptoms for a Honda SS Auto:

    1) Poor shifting into reverse, especially during cold weather. Kind of clunks itself into the reverse from Park. (There is a noticeable shutter.)

    2) Poor shifting into D4 from Reverse. Once again, Clunks itself into gear.

    3) Hard shifts from one gear to another. Typically, 3rd to 4th gear shifting. (Imagine a steel I-beam being hit by a sledge hammer, and that's what this failure feels / sounds like.)

    4) Finally, failure: Slips and never engages the next gear.
    What can be done to extend the life of your SS Auto?:

    Well, there are quite a few simple things that will extend the life of your SS Auto.

    The first thing is to install a transmission cooler in line with the existing cooler. This will keep the overall temperature of the transmission below 200 degrees. (Ideally, you want it to be about 175 degrees F.) Be careful not to install too large a cooler, as you need to keep the trans temp up into the normal operating temps during the winter. Purchase a medium sized cooler! Not a small one, and not the largest one that is made...

    The second thing you need to do religiously is change your ATF with Honda ATF every 15,000 miles. ESPECIALLY IF YOU DO NOT HAVE AN AFTERMARKET TRANSMISSION COOLER INSTALLED.

    Why 15,000 miles? Most Honda dealers will tell you it's a really good idea to change the ATF every 30,000 miles. (Even though the Service Manual says 90,000 and 60,000 miles depending on driving conditions. [what BS!]) However, you can only change 3 QTs at a time with a standard drain. As such, if you change the ATF every 15,000 miles you are removing particulates and refreshing the ATF's additive package (which prevents the acidic worn out ATF from effecting the transmission and keeps the seals in good condition).

    Lastly, if you live in climates where you are going to face sub-zero temperatures, then you should consider using a synthetic ATF / Honda ATF mix. Generally, you can use 50%-60% Honda ATF and AMSOIL or Mobil 1 Dexron III ATFs. You can also use B&M "Synthetic Trick Shift" ATF, it flows to -65 degrees F, but is better mixed with AMSOIL or Mobil 1 as well. You will likely need to have at least 50% Honda ATF in your transmission to maintain proper shifting characteristics. It’s possible that some of the current market ATFs have been reformulated to meet the friction requirements of Honda ATF, but you can not count on that!

    Interestingly, Honda ATF only thickens slightly at 0 degrees F. B&M, AMSOIL, and Mobil 1 have virtually no change at 0 degrees F and that's why the mixture works so well. (Better cold shifting, slightly better thermal transfer properties, improved lubricating properties, etc...) Keep in mind that if you use B&M "Synthetic” Trick Shift ATF it's not actually a truly synthetic fluid and will need to be changed at the proper 15,000 mile interval. B&M does have much better cold shift characteristics, but that’s because it’s a thinner ATF to begin with. (Even with synthetic ATF in the tranny you should change it regularly anyway, but especially when using Honda ATF or B&M STS.)


    5th Gen SS Automatic to 5 Speed Swap Wiring Information


    I've been getting a ton of messages from people interested in knowing how to wire their 5th Gen Prelude after converting from the SS Auto to the 5 Speed Manual Transmission.

    It seems that many folks are having problems with a lot of simple concepts in respect to automotive wiring. Such as:

    - What is pin?
    - What is a connector?
    - What is a wiring harness?
    - How do I find the Automatic Transmission Gear Position Sensor (ATGPS for short) and its harness?

    The first thing you need to have to begin this work is the Helms manual for the 5th Gen Prelude. If you don't have it, then get it. Period. You need to be able to look at the pin-out chart for the ATGPS to do this job. (Please do not send me emails if you are too lazy to look things up in the Helms manual.)


    PIN: (aka electrical contact) Pins come in both male and female varieties. The male side slips into the female side (obviously) creating an electrical connection or "conducting" current to complete the circuit.

    CONNECTOR: This is the housing the holds a bunch of pins. On a Honda they are generally gray, but can also be black, blue, green, or orange.

    WIRING HARNESS: This is the set of wires that generally connects one part of an electrical system to another part of an electrical system. Typically, a car will have a complete wiring harness for the engine bay that covers all of the electrical components and connection around the engine (et al).

    RELAY: A device that responds to a small current or voltage change by activating switches or other devices in an electric circuit.

    OPEN: An electrical term meaning that the circuit is open. An open circuit is one where current can not flow because their is an break in the wire or an interruption from a turned off switch, relay, etc.

    SHORT: An electrical term that means the circuit is closed. A shorted circuit or "Short Circuit" is one where current is flowing between one or more points. An example of this is a closed switch: When the switch is closed it is turned to the ON position and current flows through it. A "Short Circuit" can also be when current is (for some reason) flowing somewhere it shouldn't be. An example of that would be dropping a long screw driver on the battery of your car and having the + (positive) and - (Negative / ground) terminals connect. (Resulting in a spectacular explosion or the destruction of your screwdriver and battery and God knows what else.)

    Getting started:

    Open the Helms Manual to Page 14-108:

    First, the best thing you can probably do is to remove the Auto Trans Gear Position Switch (ATGPS) from the automatic transmission when you take it out of the car. [You can then cut off the switch and use the wires on the remaining portion of the harness (that was attached to the switch).]

    In the Helms manual you will note that there is a switch attached to a wiring harness. That switch told the automatic tachometer to display which gear the car was currently in. It also told the TCM (transmission control module or "brain" for the transmission) what gear the car was supposed to be in.

    Removing the ATGPS is done using the standard 10mm socket that most of the Prelude is disassembled with. Once you'd removed the ATGPS from the transmission, you need to take a pair of dikes (aka cross-cutting pliers) and cut the switch part off the harness.

    Once you have the harness and switch separated you can then solder or bullet crimp the wires you'll need to connect together. [I HIGHLY recommend that you solder and heat shrink every connection. If you do not have familiarity with doing this, get someone to help you. Since this is going to be in the engine compartment, it needs to be durable.]

    Using the ATGPS will prevent you from damaging the car's wiring harness by tapping into it using such things as bullet connectors, wire taps, and so on. The Prelude's engine bay wiring harness can only be purchased as a whole unit for about $500.00. So if you wreck it, it's going to cost you!

    Hooking things up:

    Look at page 14-109 in the Helms manual.

    This view shows you where the ATGPS hooks into the wiring harness for the car.

    NOTE: The male side is the ATGPS, and the female side of the connection is the car's wiring harness.

    Now look at page 14-107 in the Helms manual.

    This page shows you the actual pin-out view of the wiring harness for the ATGPS side of the connection (between the ATGPS and car's wiring harness).

    So, if you are holding the ATGPS connector in your hand and looking at the pins, you would see what is at the top of page 14-107 (just pins themselves not a bunch of numbers).

    What this does for you is that when I give you which pins you need to use, you'll look at the other side of the pin in the connector and find out which wire corresponds to that pin. [I don't remember what color the wire are, and some folks are color blind.]

    Reverse - Backup Lights:

    The reverse lights should be connected directly to the ATGPS harness by soldering wires to pins 3 and 9 using a male and female bullet connector.

    The manual transmission has a backup lights switch with two connectors attached to it. These connectors are male and female bullet connectors. To properly create the connection you'll need your own bullet connectors and a piece of wire. Pin 3 is actually used for two connections, so you don't want to connect the bullet connector directly to the wiring coming off of pin 3. Pin 9 you can solder or crimp a bullet connector directly two as it's only used for reverse.

    It turns out that the bullet connectors on the backup light switch on the manual trans are exactly the same as the ones for the LED (light emitting diode) array in the wing. I had an extra set of LED's... so I chopped off those connectors and used them. They are rubberized and a perfect fit.

    How the reverse circuit works:

    The reverse switch works by completing the circuit and energizing a relay that turns on the backup lights. Pin 3 is a 12 volt feed line that provides low level power to any circuit attached to it. Pin 9 is the side of the circuit that energizes the relay when power is applied to it. The reverse switch shorts pin 3 and pin 9 whenever the manual transmission is in the reverse gear, thus turning on the backup lights.

    Clutch Starter Cut Off:

    If you don't care about being able to start the car with it in gear, then you can solder the wire coming off of pin 3 to pin 1. The car will always start, even without you foot depressing the clutch.

    If you want the car to not start when the clutch is NOT depressed, you need to run a pair of wires to the clutch [top switch] from the wires on pins 3 and 1 of the ATGPS harness. There are two switches on the clutch: one that works when it's fully depressed (starter enable), and one that works when the clutch is not depressed (cruise control enable).

    What you need to do in this case is you need to run some decent 16 or 14 gauge wire from the wires on pins 3 and 1 thru the firewall and into the car where the clutch is. The most professional way to attach the wires to the clutch switches is to have gotten the connectors from the wrecked Prelude that you got your swap stuff from. Then you simply connect the two wires to the switch by soldering the wires you've run to connectors you've gotten from the wreck. [One of the switches has more than 2 pins, so you need to take a voltmeter and verify connectivity on the two pins you are going to use.]

    How the Clutch Starter Cut-off works:

    Pin 3 provides a 12 volt feed to the circuit. Pin 1 provides current to a starter cut-in relay that enables the ignition to energize the starter relay. When the upper switch on the clutch is engaged (peddle is down) the circuit is shorted and current from pin 3 flows through the switch to pin 1 allowing the car to be started.

    Cruise Control Cut Off:

    The cruise control circuit needs to be grounded for it to be active. So, this means that you need to ground the wire on pin 2 of the ATGPS for the cruise control circuit to work. So you need to run a wire (in addition to the 2 for the clutch cut off circuit for a total of 3) to the lower switch on the clutch from the wire on pin 2 of the ATGPS harness. On the other side of the lower switch on the clutch, you need to run a wire to any grounding point in the dash board area near the clutch.

    How the cruise control circuit works:

    This circuit is always turned on when the clutch is NOT depressed. The moment you put your foot on the clutch pedal the connection to the dash board area ground is interrupted and the cruise control turns off because the lower clutch switch is now open.

    Once you've done all of the above your Prelude will work just like a factory 5 speed.


    Everything You Can Do to Troubleshoot Your SS Automatic.

    As many of you are probably aware, Honda has seen fit to warranty the 2000 and 2001 model year Prelude transmissions to 100,000 miles. Unfortunately, this leaves the owners of the other 3 model years of the 5th Generation of the Prelude to pay for expensive rebuilds themselves.

    However, all hope is not lost! The Sequential Sportshift Automatic Transmission is an electronically controlled fluid coupled transmission, and there are many problems that can be fixed without need to replace the transmission. You need to know what can go wrong so that you are not sold a new transmission because you didn’t know what the problem really was!

    Most of the user fixable transmission problems are going to be electrical (wires and solenoids).

    Getting Started:

    First, there are a few diagrams in the 1997-1999 Helms manual that you’ll want to look at:

    1) Page 14-53 shows the external transmission components that are involved in the normal operation of the automatic trans.
    2) Page 14-16 shows a list of Shift Control Solenoid Valve positions and what gears they effect. (more on this later)
    3) Pages 14-102 to 14-106 show how to test all of the external components specific to the transmission.
    4) Pages 14-114 to 14-117 show which components to check based on the symptoms you are experiencing.
    5) Pages 14-116 and 14-117 show typical causes during rebuilding that will cause specific problems. So if you’ve had your tranny rebuilt and it’s acting up, you’ll want to check these pages.


    To figure out what type of problem you have you should know the basics of how an automatic transmission (auto trans) works.

    Basically, an auto trans uses hydraulic pressure to control the functions of the transmission (trans). These functions include controlling the clutches (1st thru 4th), locking up the torque converter, cooling the trans & torque converter, and lubrication.

    The fluid used in the trans is generally called Automatic Transmission fluid (ATF), and circulates through the trans via a variety of pathways cut into the various steel and aluminum components.

    Flow the ATF in the various components controls exactly which gear the transmission is currently shifted into by placing ATF pressure in a series of stacked plates (clutches) that in turn put the transmission into gear. (This is a somewhat simplified explanation.)

    The flow is controlled by 6 solenoids (with the help of you car’s Transmission Control Module [TCM]):

    1) Shift Control Solenoid A
    2) Shift Control Solenoid B
    3) Shift Control Solenoid C
    4) Lock-Up Control Solenoid
    5) Pressure Control Solenoid A
    6) Pressure Control Solenoid B

    From High School physics you probably know that liquids are basically uncompressible. As such, applying pressure to the ATF causes it to flow through the pathways in the trans. The exact direction and components that the pressurized ATF is applied to are controlled by a combination of the Pressure Control Solenoids, Shift Control Solenoids, and the Lock-Up Control Solenoid.

    When ATF is applied to the various internal clutches in the trans they engage and cause the vehicle to move in the corresponding gear. So, if ATF is being pumped into 1st gear clutch then the car will begin to move in 1st gear, and so on.

    Knowing what kind of problem you have:

    Problems with your SS auto trans are probably going to fall into one of the following categories: Mechanical, Electrical, or ATF.


    Honda recommends that you use only Honda Z1 ATF in your SS auto. This is fairly important if your ride is still under warranty.

    Honestly, Honda ATF is pretty good, but it’s not so great a sub zero temperatures. I’ve been using Mobil 1 synthetic ATF for some time and it works very well. If you are facing subzero temperatures, then you may want to consider using Mobil 1 synthetic ATF. I make no warranties as to how it will work in your car, but it works fine in my 1998 Prelude.

    There are a few problems that involve ATF.

    First, if your car rolls in Neutral, then the problem is probably that you have TOO MUCH ATF in your trans. During a normal ATF change in the 5th Gen Prelude you can put as much as 3 QTs into the unit without any problems. More than that and the car might start to roll in Neutral.

    Second, if you car doesn’t move at all when you put it into gear, then you probably don’t have enough ATF in the transmission. Check the dipstick and verify you actually have enough ATF. The ATF should be at the top of the hash marks on the dip stick.

    Third, under the Shift Control Solenoid A / Lock-Up Control Solenoid assembly is a rubber gasket with two small screens embedded in it. If the ATF has not been changed regularly (every 15000 to 30000 miles), then the screens can begin to clog with small metal particles that are part of the normal wear of the transmission. Generally, these screens can be cleaned and reinstalled (though Honda indicates that they should be replaced upon inspection to prevent ATF leakage). The symptoms that this form of problem causes will vary depending on which solenoid is clogged:

    Lock-Up Control Solenoid
    - Low torque converter stall speed.
    - Engine idle vibration
    - T/C lock-up clutch does not engage / disengage.
    - Lock-Up clutch does not operate smoothly.

    Shift Control Solenoid A
    - Vehicle does not move in the 2 position on the Shift Control Lever.
    - Trans erratically fails to shift in D4 from 1st to 3rd.

    Note: There is a way to monitor the health of the internals of you trans by sending your spent ATF out to a laboratory at every ATF change. Lab services will analyze your ATF and determine exactly how well it’s holding up. They will also tell you what wear metals are present. Knowing the level of wear metals will give you a heads up about any imminent mechanical failures.

    Two companies of note are:

    Oil Analyzers at

    Blackstone Labs at


    Mechanical problems with your SS Auto Trans tend to be somewhat obvious.

    First, if you notice problems and then drain the ATF and find a LOT of metal in the drained ATF, then you’ve probably got a serious mechanical problem. NOTE: If the ATF also smells burnt (like a fireplace you’ve put plastic into), then you definitely have an internal mechanical problem).

    Second, if you check you fluid levels and the outside temperature is not below freezing AND your tranny makes a whining or whirling noise, then it’s likely you may have a problem with your T/C.

    Third, if you shift into any gear and the transmission BANGS (aka Hard Shifts) into the next gear AND you’ve checked all of the potential electrical problems, then your transmission probably has a mechanical problem. Probably either bad bearings or bad clutches. (The SS auto is known for have bad 3rd gear clutches.)

    Fourth, if you shift into any gear and the transmission slips and never quite makes it into gear AND you’ve checked all of the potential electrical problems, then your transmission probably has a mechanical problem. This is likely a bad clutch.

    Lastly, if you hear grinding, you’re screwed. It’s probably caused by bad bearings. You need a rebuild. (You probably saw a lot of metal in your ATF… if you have ATF Pressure.)


    Electrical problems can cause just about every problem except grinding in you SS Auto.

    (Though ignoring an electrical problem could conceivably lead to a mechanical failure of the transmission.)

    It is important to note that many of the electrical problems that might be encountered with an SS Auto will not generate a Malfunction Indicator Light (MIL) on the dash board or cause the D4 light to blink once the engine is running. If you encounter a problem and are familiar with checking codes you can find out if you car’s computer has noticed any problems and stored any Diagnostic Trouble Codes (DTC’s). Page 14-54 to 14-59 of the 1997 – 1999 service manual cover how to view codes and troubleshoot them.

    Shift Control Solenoids (SCS) A/B/C:

    The Shift Control Solenoids (SCS for short) can cause a bunch of symptoms that generally deal with poor shifting (harsh shifts, long shifts, etc.) or a complete failure to shift into the proper gear.

    The SCS’s work as 3 bit binary system that controls the flow of ATF to various parts of the transmission. The flow of ATF is controlled by the position of the 3 solenoids which in turn effect the shifts of the transmission into the different gears (via pressurized clutches). As such the smoothness of the shifts is controlled by intermediate positions of the solenoids.

    Take a look at Page 14-16 in the service manual. It has a table that shows what the trans is doing in relation to the 3 SCS’s.

    If your transmission is only having a problem at higher RPM’s (which would equate to higher ATF pressure), then it’s possible that you have a problem with one of the SCS’s or the ATF Pressure Control Solenoids (PCS) [we go over them next].

    Use the instructions in pages 14-102 to 14-106 to check any of the solenoids.

    Typical problems with the SCS’s will cause many different problems (see pages 14-114 and 14-115 in the service manual):

    - Vehicle does not move in a specific gear.
    - Late shifts from Neutral to D4 or D3.
    - Late shifts from Neutral to R
    - Fails to shift from D4, D3, or 1 – and starts out in 3rd gear.
    - Excessive shock or flares while shifting to/from ANY gear.


    If you need to replace either SCS B or C, then you need to be very specific with the Honda Parts person you deal with. The 1997-1999 Helms Honda Prelude Serivce Manual shows the location of the 3 SCS’s. Unfortunately, the Honda Parts system lists the solenoids incorrectly. They show the B solenoid as A, and the C solenoid as B. The best way to insure that you get the correct one is to bring your manual and show it to them. Also, the B solenoid is BLACK and the C solenoid is BROWN. If you ask for the C solenoid (to solve harsh shifting from 3rd to 4th for instance) and they come out with a black solenoid, you’ve been given the wrong one.

    Clutch Pressure Control Solenoids A / B:

    The Clutch Pressure Control Solenoids (CPCS) are controlled (like all the others) by the Transmission Control Module (TCM). The TCM regulates which gear the transmission is in by activating / deactivating the CPC solenoids. The output of the CPC solenoids are moderated by the SCS’s to control the smoothness and precission of the shifts from the various gears.

    Problems with the CPCS’s will cause the following issues:

    - Excessive shock or flares in an ALL shift lever positions.
    - Late shift from Neutral to D4, D3.
    - Late shift from Neutral to R.
    - Lock-up clutch does not engage, disengage, or operate smoothly.

    Lock-Up Control Solenoid (LUCS):

    One of the features of a modern auto trans is generally the ability to “lock” the torque converter (T/C). I’m not going to cover everything you should know about a T/C, but here is a good article on the basics of what it is and how it works. You want to pay close attention to the lock-up feature:

    The 4 speed M6HA Honda Prelude transmission has 4 gears and a feature called “lock-up.” The T/C is connected directly to the engine. At various points in various gears the speed of the engine will begin to match the speed the 2nd half of the T/C is spinning at. At that point it becomes more efficient to have the T/C actually spinning at the same speed as the engine. When the TCM notices that the engine speed and T/C speeds are within a certain number of RPM’s of each other, it actives the Lock-Up Control Solenoid and the two halves of the T/C spin at the same speed. This is more efficient than using the normal fluid coupling of the T/C, and has the improved benefit of improving gas mileage.

    One last feature of the T/C is known as Stall Speed. Stall speed is basically the number of RPM’s that the T/C needs to be rotating before the car will begin to move (aka the transmission is engaged). The optimum stall speed is determined by the horse power and torque that the engine produces coupled with the style of ride you are looking to achieve. Most vendors go for a smooth ride as opposed to an aggressive ride. (Smooth starts as opposed to abrupt starts. The T/C’s stall speed affects this.)

    Failure of the LUCS causes:
    - A low stall speed. (The service manual indicates it should be 2500 RPM.)
    - Engine idle vibration.
    - Lock-Up Clutch does not engage, disengage, or operate smoothly.*

    * Honestly, it’s going to require a little bit to testing to determine that you have a LUCS issue. If the LUCS doesn’t work, you may never know. If it works poorly, then you’ll probably need to start testing all of the various components and eventually arrive at the LUCS.

    One way to potentially tell if the LUCS does not work is if your gas mileage suddenly goes down dramatically, which would tell you that the T/C is not locking up like it should.

  2. #2



    I have combined your 3 threads into one superthread so I can sticky it. Thank you Gerhard for this incredibly informative and in depth post. The title truly says it all.

  3. #3


    Wow almost exactly 3 years later and I'm restickying this thread! Thanks boske for helping me relocate it.

    Due to the sudden increase in questions pertaining to the automatic transmission in 5th gen preludes I have restickied this invaluable post, and I think I'll leave it stickied this time as I expect that as the remaining unaffected cars get up in age and mileage, we will only see more questions regarding this problem.
    Hope this helps.

    I'm also going to leave this open for comments in case anyone has anything new to add that may help others.

  4. #4
    New Member
    Join Date
    Oct 2006
    in the land of milk and honey served on a platter by topless 22 YO's


    As you can see in my sig, i had an 02 TLS. I had the tranny replaced 3 times by honda reman'ed trannies. The fourth time, I demanded a brand spanking new tranny, which the district service manager kinda demanded that if that tranny failed, he would find out what i was doing to mess them up...! Long story short, the brand new one never failed...

    Here is the part that adds to your thread and helps anyone who needs to address the issue with the service rep and/or mechanic.

    Fist time the tranny started slipping, I left it with them and they called me at work about an hour after dropping me off(no loaner car) that nothing was wrong with the car. I told my supervisor I had to take the rest of the day off to get this resolved...they picked me up. I took the mechanic on a test drive and soon as i could get out of traffic, i tried shifting from 2-3 gear in SS mode and it locked just hit the rev limiter until i let completely off the gas. Mechanic told me right then and there that the tranny had to be replaced(no shit i thought)...after that first incident, it only got progressively worse as i got pushback from the service reps on failure 2 and on failure 3 i spoke to the service manager and stated i would only request a NEW tranny if replacement 3 failed...which it eventually did, when i was about 120 miles from home.
    it's all about the ride...

  5. #5


    thanks systeq for sharing your experience. Good to see you got it resolved. The sad part is they likely were very aware that it was a common defect while giving you the runaround.

  6. #6
    New Member
    Join Date
    Oct 2006
    in the land of milk and honey served on a platter by topless 22 YO's


    Quote Originally Posted by Harry
    thanks systeq for sharing your experience. Good to see you got it resolved. The sad part is they likely were very aware that it was a common defect while giving you the runaround.
    NP, the best advice I can tell others is to be informed...i knew about the tranny problems cause I was a member of an acura forum
    it's all about the ride...

  7. #7


    I just bought a 2000 prelude sport shift automatic transmission and it has 98,000 miles on it. Can i take it in to the dealer for them to check out the transmission or how does it work.. I do feel like the transmission is shifting too slow. HElp!

  8. #8


    If all it's doing is shifting too slow I doubt it's going, I would wait until you start seeing more symptoms than that.
    A little advice: Don't take a car that isn't broken to the dealer and ask them if it's broken.
    Last edited by Harry; 10-11-2008 at 07:30 PM.

  9. #9


    I read all of the SS Auto transmission failure symptoms, and I don't quite fall under any of the categories, but I do notice something weird with my tranny. Every now and then if I'm sitting somewhere with the car running for a while I'll put the car into neutral, and sometimes when i go down into D4 my entire car shakes, sometimes lightly, and sometimes really violently. Is this another sign of failure? Any help would be great. Thanks!

  10. #10


    I bought a new tranny and am almost all the way done taking the old one out, although Ive run into problems because wiring is the only thing stopping from the tranny coming out. What do I need to do? What pages is the transmission stuff in on the manual?

  11. #11


    Hello. I am about to swap my 98 trans out for my known good 97 auto trans. It hard shifts into d4 and other forward gears. However, in reverse and neutral it moves forward when I rev the engine. Thinkn shift fork is is broke....

  12. #12


    Quote Originally Posted by wldr56 View Post
    Hello. I am about to swap my 98 trans out for my known good 97 auto trans. It hard shifts into d4 and other forward gears. However, in reverse and neutral it moves forward when I rev the engine. Thinkn shift fork is is broke....
    Mine was the same way, but within days it started shifting hard into 3rd and reverse, and eventually didn't want to shift past 3rd. I went through everything and it was indeed my tranny so im going to assume you're having the same problem.

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