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View Full Version : Hey you Tranny Guru's


godtool
04-11-2009, 06:54 PM
I bought a 83 GMC 3/4 ton 4x4 pick-up. It has a 1974 small block 350 with newer style heads, center bolt style. It also seems to have a 5 spd automatic: With the 4:10 diff ratio, it hits 3rd by the time you get across an intersection, 4th around 80 kms-90 and then past a 100 it seems to shift again. I read in my 1999-2006 Haynes Manual the 4L60E and 4L80E "are equipped with a torque converter clutch (TCC) that engages in 4th gear" P. 7B-1. If anyone here has a 4L60E or 4L80E does this TCC feel like a "5th shift"? Next to do is hook a tac up to see the rpm's drop in 5th...

Heres the link I found on tranny ID:

http://www.maliburacing.com/auto_tranny_id.htm

nbrowser
04-11-2009, 07:02 PM
There should be about a 50RPM drop when the torque converter locks up, not much more drop than that.

Nutbar
04-11-2009, 11:40 PM
Unless somebody has done a fuely swap with something 94 and newer it won't be a 4L tranny the 4L trannys are fully electronic and require a computer to work. The truck is probably a 700r4 tranny, 4 spd auto with lock up converter. If it has a TV cable (cable hooked up to carb linkage) and a 4 wire plug on the side of the tranny near the shift linkage it is a 700r4, common tranny for mid 80s to mid 90s GMs

tchevy
04-11-2009, 11:47 PM
There should be about a 50RPM drop when the torque converter locks up, not much more drop than that.

i think you forgot a zero.

it should be about 500 rpms.