This table is provided for entertainment only. No warranty is expressed or implied as to its accuracy. Typographical errors are possible. Please send any corrections or additions to Rich. Many thanks to Ken Carothers for posting the original ratios table, and James Butler for posting the 4T65-E history, in the "Poncho" mailing list.
|Rear Wheel Drive|
|Front Wheel Drive|
Here is the rough lineage of the 4T65-E: Designed Yr.- Production Yr.- Model 1974 - 1978 - THM-125 (3T40) - Some bushings & bearings carried from THM-200, some basic designs of splines & shafts from THM-200 and THM-350 1980 - 1983 - THM-440T4 (4T60) - Four speed version of THM-125. Some parts identical or very similar. Somewhat stronger than THM-125. 1983? - 1986? - F-7 - Made exclusively for Cadillac Allante. Similar design but many parts different to improve torque capacity. More expensive. 1985 - 1988 - 4T60-E - (F-31) Electronic shift version of THM-440T4. Most parts identical to THM-440T4. 1991? - 1993? - 4T60-E HD - Same as 4T60-E except with a few heavy duty parts (mainly final drive gearset) for supercharged 3.8l V-6 application. 1992 - 1997 - 4T65-E - Very similar to 4T60-E with many common components, but many major differences also. Below is a synopsis of a previous post with more description of changes between models: A little history on the 4T60 used in FWD GM vehicles. Best viewed fixed font. The THM440-T4 was introduced in 1984 on the new GM full sized luxury vehicles (Oldsmobile Regency 98, Buick Park Avenue, Cadillac Sedan Deville - remember the logo on the trunk lid "4-Speed Automatic"). This transmission was basically the THM125-C with an overdrive added on. The original 440 was not very reliable. Many changes were made the first 3 years. Areas that suffered many failures were torque converters (clutch rivets), 2nd clutch housings, 4th clutch area, final drive. When the Cadillac Allante was introduced, the 440 would not handle the torque of the V-8, so a special version known as the F-7 was developed. It included special sprockets, heavy duty final drive, special fourth clutch, etc. A rare but solid transmission if you can find one. By 1988 the quality was better, but to make the 440 (now called the 4T60) a world class transmission, electronic controls were added. The new transmission was coded F-31 and became known as the 4T60-E. The 4T60-E was phased in from 1988 to 1990. You can tell by looking at the bottom oil pan - it will be stamped with "4T60-E". This transmission has much better reliability. By the 1991 model year, all FWD Overdrive transmissions were the 4T60-E model. As a side note, with the introduction of the Northstar V-8s, a new low volume transmission was developed for these applications. It is known as the 4T80-E. Very durable but very expensive, about 80% higher in cost than the 4T60-E. Also 60 pounds heavier. With the introduction of the Supercharged 3800, a few modifications to the 4T60-E were made. The biggest change is the final drive unit, which is of heavy duty design. The transmission still can't handle the full torque of engines such as the SC 3800 and the DOHC 3.4L V-6s at redline during shifts. GM utilizes Engine Torque Management to maintain reliability. This consists of controlling engine rpm and engine torque (through timing and fuel) during shifts. That is why the SC 3800 and DOHC 3.4L do not shift at redline at WOT. For the 1997 model year, GM introduce the 4T65-E. This transmission is a heavily reworked 4T60-E design which includes such features as a 258mm torque converter instead of 245mm, twin chains and special sprockets for noise, Electronic Line Pressure (ELP) for ECM control of pump pressure to better regulate shift quality, revised fourth clutch, revised second clutch housing, and many other improvements to reliability. The first applications to receive the 4T65-E will be the SC 3800 V-6 and the DOHC 3.4L V-6 to minimize the need for torque management. The phase in will be three years and will be complete by model year 1999. The biggest cause of failure of the original 4T60 (440) is heat. [snip of restricted info] Through control of shift points and torque converter lockup, tranmission temperature can be controlled. There is a temperature sensor in the transmission for the ECM to monitor. This shows the STRONG recommendation to add and external air/oil transmission cooler for 4T60 (440) equipped vehicles. The following is a list of GM FWD transmissions and their applications: Model Years Current Application --------------- ------------ --------------------- THM125-C (3T40) 1979-2002 J (possibly to 2002) 4T40-E 1995-future J,N,P-90 THM-440T4 (4T60) 1984-1990 None 4T60-E 1988-1999 All except J,N,P-90 4T65-E 1997-future SC 3800, DOHC 3.4L 4T80-E 1992-2002 Northstar Steve Ochs aka N8TYS- Mfg. Engineer - GM Powertrain - Parma Plant Transmission Division (4T60/65-E) - The statements and opinions expressed here are NOT an official statement of General Motors or the GM Powertrain Division
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