Transmission Identification

[heavyredchevy]

1989 K1500 ext-cab longbed 5.7L TBI Auto w/overdrive

I was woundering what transmission was in my truck (how can i tell), It has a square pan with 16 bolts and it doesnt appear to have a modulator. From what im hearing its either a TH700R4 or a 4L60E.
Also I plan to put a 383 stroker kit in later on, and i was woundering how much HP/TQ these transmissions can handle.
Thanks,
Ryan

[cbongo247]

your 89 most likely has the 700r4. not the best tranny, but better than the 86s and older. they are easily built and can handle around 400hp range. fairly durable. the 4L60s came out in 90 or 91, then were upgraded to the 4L60Es in late 93. the E stands for electronic overdrive. as long as you chang the fluid and keep these two trannys cool, they will treat you well. unless you are planning on major wiring upgrades and swaps for the 4L60e, your best be would be to go with a rebuilt or built 4l60 depending on your budget. but a I would highly reccomend at least a 2500 stall converter, i have one in my 94. great on the street and even better at the dunes! also install a shift kit. high performance or towing modle wichever has a more firm shift. any more qs let me know.
kyle.

[heavyredchevy]

The stroker kit is going to put out 408 Hp @ 5,500 and 446 ft lbs @ 3,500 RPM, so the trans probably isnt going to handle it. Can I overhaul the trans i have, or will i have to go with a different trans, such as the 4L80 or a TH400. Also what about the transfer case, and what does a 2,500 stall converter do?

[CHIP1218]

i would go with the 400 or if you can afford it, the 4L80E. the 4L80E is basically the electronic overdrive version of the 400. both can handle a lot of abuse. the downfall of the 4L80E is that it is all computer controlled therefore it wont operate without a control module and the price of the trans can be a little steep as well as the control module. Jegs has the control module part# 890-377000 but it goes for $660.00.