GM Transmission Information (Looking for Engine info? Click here)
This page has been set up to bring you the most accurate and up to date information on GM transmissions that is available to us. This information should be used as a guide only. While we have made every effort in making the information presented here as factual as possible, but there still could be some discrepancies or errors. If you have any questions, comments, or suggestions, please give us an email.
Front-Wheel Drive Transmissions
4T40-E / 4T45-E
4T60-E -- click here for Application ID charts
4T65-E -- click here for Application ID charts
FWD Transmission Gearing / Chain Information Table
Rear-Wheel Drive Transmissions
GM RWD Torque Converters
Starting 1980-up, GM used a 4-digit ID sticker located on the converter body to help identify it. Below is a guide to help decipher it's meaning.
1st Digit (application trans)
2nd Digit (approx stall, depends on engine)
3rd Digit (Clutch Assembly)
4th Digit (Body Mounting)
If there is no ID tag, there might be a number or letter stamped between the dimples of the impeller on the converter body.
GM FWD Torque Converters
GM uses the same type 4-digit ID method of identifying FWD torque converters as with the RWD units, however the digits have different meanings. All 125-C, 440-T4, 4T60, and 4T60-E transmissions use the same style torque converter, and they are interchangeable before 1996. 1996-up converters are built to be compatible with GM's PWM TCC apply strategy which means that you can use the newer converter on the older trans, but not the older converter on the newer trans.
1st Digit (application trans)
2nd Digit (approx stall (depends on engine)
3rd Digit (TCC clutch material)
All other digits (pre 1996):
4th Digit (Clutch Type)
Pertaining to the TCC Clutch material: starting in 1996, GM implemented a new TCC apply strategy. The 1996-97 trannys (exc 3T40), used a soft-apply (PWM) TCC strategy which was designed to soften the TCC apply so the "customer" would not feel it come on. This means that the PCM is actually making the TCC slip during apply. Only Carbon clutch torque converters should be used in 1996-97 trannys. You can use the carbon clutch TC's in earlier trannys that did not have PWM technology, however the lockup feel will not be the same. However, I have heard that these carbon clutches rarely burn-up or go bad. I have personally used the carbon filled clutch TC's on earlier trannys and the only experience I have witnessed with them is they apply firmer.
Starting in 1998, GM revised the lock-up strategy once again only this time the TCC may never completely lock up and may always slip about 20-60 rpm, depending on the vehicle. This means that even the carbon clutch units would not work well for these applications thus GM started using woven-graphite TC clutch material. I have heard that the woven graphite TC's should not be used in any earlier transmissions because the lockup will not work correctly.
This information should be used as a reference guide only. Please consult your local dealership or transmission shop for your specific application and needs.
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