I'm having my transmission rebuilt (at the factory) and I ran into a slight problem. I was wondering if anyone could help me find out the differences between a 1992 Astro Van 4L60 and a 1992 Z28 4L60. My car's last tranny was a 700R4 from a 1986 IROC. The case, pump, and converter were gone. I deceided to return to the original tranny........a 1992 4L60. I was told that the only difference between any 4L60 was the tailshaft housing, but that seems to be incorrect. My tranny is now back in (with an Art Carr shift kit) and it is worse than stock. The 1-2 shift duration is like 3 seconds instead of the .2 it was in all my other tranny's. It actually drives like and Astro Van. I asked the shop that did my last transmission about it and he said the valve bodies were different. He also rambled out alot of other stuff (which I can't remember) that is different. I have all the parts from the 700R4 (springs, valve body, etc...), but I'm not sure what I can use from the 700R4. Any help would be much appreciated. Thanks.

 

keep in mind that 4l60 and 700r4 are same thing, 93 went from 700r4 to 4l60E

cant be a whle lot different from one 85-92 700 to another, unless one is V8 one and one is V-6 one or something,
but who knows,
im curious about this one,.

 

TTT

 

Don't take my word for it, but I think the biggest difference between the 700r4 and the 4l60e is the name. Gm started using a different naming system in 93.

 

As far as I know, there are a couple of big differences. First, the number of frictions and steels used in the different clutch packs will be different. This will effect the amount of torque the tranny will handle. The valve body will most likely be different. The servos will be different. The main boost valve will most likely be different too. Basically, the trans from an Astro is not designed for performance. Its for comfort. As far as using parts from the 700, I believe the big changes in the design ocurred in 87. I don't think your gonna have much luck stealing parts from the 86 trans to put in a 92 trans.

 

Use the Valve Body, Seperator Plate, Servo (or get a 'Vette Servo), Governor, Pressure Regulator Assembly, Accumulator Springs, Rear Planetary, Harness, Switches and Tail Housing from the Z-28 and it will BE a Z-28 Tranny.