I'm running the 700R4 from my '84 5.0 Z/28 in my '54 Chevy pick up. I was told it's not as good as the one I have in my '88 IROC with the 5.7 motor. What year did they change and what differences are there? Thanks Daniel U

 

There were incremental improvements in pretty much every year. Probably most significant was the addition of the auxiliary valvebody in 1987. Most other changes can be retrofitted during a rebuild.

 

How did this make them better/stronger?

 

How did which, the auxiliary valvebody? It has forward and reverse accumulators to soften the initial shift into gear.

 

Thanks for the info. I like to learn as much as I can.

 

also, in 87, correct me if i'm wrong, but i thought they changed the spline count from 27 to 31, and made the input or output shaft stronger?

 

The input shaft spline count was changed between 83 and 84 in V8 transmissions, V6s still used the smaller shaft. The larger input shaft could still be put in an older case.

 

Like already mentioned the 87-up had the softer engagement via the Aux VB. But more inprovements were made in the internals like the 3-4 clutchpack which was a problem area in 89-up. IMO get the latest version. 1993 was the last year for the 4L60/700R4 B4 it became a computer controled tranny. Hence the E at the end of the 4L60E. Most 89- up are now referred to as the 4L60 trans. GM just changed and unified their ID system on the trannys. Dropping the old TH (TurboHydramatic) moniker. Hope this helps.