Two years ago, i rebuilt my th700r4 with the following parts:

Raybestos steels and clutches
Kevlar-band
Corvette-Servo
.472"-boost valve
TransGo Reprogramming-Kit Stage2/Stage3

To day, i was very happy with it. But now, i want to change the 1-2 shift. The 1-2 shift is very very firm. Now, i donīt want to have this "shift-character". I didnīt find the installation-instruction from the transgo-kit.
Which parts should i change to get a nice, smooth 1-2 shift ??

Thanks.

 

I would guess you either need to swap back the spring in the 1-2 accumulator or else the large spring in the 2nd servo piston.

Here is a list of possible springs for the accumulators.
https://www.wittrans.com/SchematicPa...4&LinkCode=926

For some reason they don't offer the servo spring. But, I'm wondering if the oil-relief notches that are ground in that steel cover have something to do with it. Every time I pull one, that is full of oil. Since there is a spring in there that must be compressed(i.e. the fluid must push out as well, that would slow things down by not grinding the notches). Aside from that and the two springs, I remember a hole being drilled out somewhere in the separator plate.

Hope that points you in the right direction.


I'm about to the same problem. Just off idle and the car throws me into the seat when 2nd hits. Above light throttle pressure and the rear breaks loose.

 

There are three 2-4 servo versions.

554 piston - stock firebird/camaro
553 piston - Van, SUV, Truck
095 piston - Corvette-Servo GM-Performance

Transgo said, i shouldīnt use the 554 piston. The 554 piston is to small. First, i used the 553 servo without the thick shock absorber spring. I corrected the band play with shims on the spoke. The 1-2 shift was very very firm.
Second, i removed the 553 piston with the transgo-shims and installed the stock corvette servo with the thick absorberspring. Now, the servo should be the correct one, because the corvette doesnīt shift very very firm.
I think, the reason of the firm 1-2 shift is the spring in the 1-2 accumulator. I want to change this spring.
The problem is. I didnīt find the transgo installation instructions and i donīt know, which spring i should use ????