Confusion over application of 4T60E.

[LakeFXGP96]

I need to clear something up and Im hoping someone can help. I need a trans for my Lumina, however im not sure what all is possible to use.

An individual has a transmission from a 91 Grand Prix that he says has '4T60-E' written on the pan, and its a factory setup. My understanding was that only the 3.4 got a 4T60-E until 1994. any ideas? would a 3.1 '4T60-E' be exactly the same as a 3.4 4T60-E of the same years 91-93?

[Rhedalert]

RE: Confusion over application of 4T60E.

3.1L cars got the 4T60E starting in 1993. 1991 for DOHC cars. The tranny's are the same as far as getting them in (pre '94 at least) but the 3.4 DOHC trans has a 3.43 final drive as opposed to 3.33 Olds Cutlass etc 3.1

[sharkey]

RE: Confusion over application of 4T60E.

gm did this in may aplications when phasing in the electronic transmissions. between 91 and 94, you could have an electronic or non electronic in different cars and motor. sometimes you could have 2 identical vehicles (motor, body, ect) and they could be and e or not (ei- our shop truck is a 93 chevy 2wd 5.7l, has a 4l60e in it, had an identical truck, production date is the same month, and it has a 700r4 in it).

anywas, the only way to tell for sure is to look at the car. does it have a cable running from the throttle body to the top of the transmission??? if it does, its a 440t4 (also known as a 4t60), if it doesnt, then its a 4t60E

[napatiger]

Suppose it is the 60E and it came out of the 3.1. We like the 3.33 right? because of the lower gearing for take off.

I was told by a trans shop that if I used a different frd that the computer would not function properly, I don't care about the speedo, but will the PCM f things up with engine management?

BTW, my mechanic friend said that he could get new 4T60-E's direct from gm for cheaper than a rebuild and they come with great warrenty.

[imported_germ]

for the gear ratio change thing....



if the difference is very small, there SHOULD NOT be ill side effects for the PCM. ex. 3.29 to a 3.33 and vice versa, however, i am currently running a 3.29 tranny, and the PCM is coded for 3.33. i DID have to change the commanded MPH shift point for WOT within the PCM for 1st gear. but i was also running on a performance tune. stock settings should be fine and not cause issues.

there WILL be issues with other gear swaps. ex. 3.05 to 3.29 or 3.33, 3.43 to any other ratio, etc....

if there is more than a 2% difference, you will probably have some drivabilty issues and shifting issues.








FYI, i would not recomend this "switch in FDR" due to the fact that IF you ever have a tranny issue, you will never know if the difference in FDR is the culprit unless you can have your PCM reprogramed.

if you do a switch, just change over your FDR to the new tranny to avoid any issues.

[LakeFXGP96]

Thanks for your input guys. I pretty much figured out that even if it was a 4T60-e from a 93 or just a factory freak, the gearing would still be different. I'm glad you guys have tried all this stuff or know enough about it. Im just starting to learn more about engines, I could have a trans filled with red fruit punch and legos and I couldnt tell the difference...