I can't recall--what does this do?
I am getting my trans rebuilt with 2400rpm stall and might add the Corvette servo.

 

It firms up the shifts. Do a search. There have been a lot of posts about this.

 

Can someone just outline briefy what the servo does? I'd really like a better ansewer before putting one in. Searching is PITA

 

freeman74
says it all pretty much, "firms the shift"

 

Using the theory of hydraulics, a larger piston surface will increase applied pressure given the same amount of hydraulic pressure. So without increasing line pressure in the transmission, you can increase the apply force on the band by installing a larger apply piston (commonly known as a "servo"). Hence the 1-2 shift will feel "firmer" and will increase the longevity of the band.

In order to obtain 3rd gear, the band must be released. So fluid that applies the 3-4 clutches is also routed to the other side of the servo to counter 2nd apply fuid, pushing the band off the drum. The pushing of the servo in the other direction acts as the accumulator for third gear as well. Since the servo increases pressure in applying, it makes it firm accumulator as well, firming up the 2-3 shift as well.

 

thanks GM tech--I now have a good understanding of the topic

 

So firmer shifts increase the longevity of the working parts in the transmission? Is it because the shifts are quicker, therefore taking less time and putting less continous stress on the parts?

 

The harder it hits, the less time it has to slip into place. Summed up in one sentence.

 

The faster a component applies, the less slip there is during the transition from off to on. However, you need to find a good balance between quickness, and comfort. A shift thats too firm can be uncomfortable and jolt the rest of the internals enough to cause damage.

 

I have that exact thing in my 700r4. Firms all shifting up NICE AND FIRM me likes!

 

I replaced the LG4 with a carb L98 engine in my '85 Z28 and since then, cannot get the 1-2 shift to change without slipping at WOT.

No matter how I adjust the TV cable, the shift is useless. It has a Holley on it and I have the TV cable bracket Holley recommends but it's still ****house! It always shifted pretty well with the peanut engine but I guess the 350 makes too much torque for it. Would a vette servo fix this?

I run the TV cable adjusted such that the light throttle shifts are too harsh, just so that I minimise and damage due to the slippy shifting. With the vette servo, will I get a smooth light throttle shift and a decent WOT shift? Do I need the vette TV boost valve and spring as well?

As a daily driver, I prefer a smooth light throttle shift but don't want a slipping shift at WOT.

 

You could install the Corvette servo and the larger boost valves to start with, but the HD or Street/Strip Shift kit will do what you want as long as the band & clutches are still in good shape. If the 1-2 & 2-3 shifts at light throttle to medium throttle are still ok, then this should solve the problem for awhile. Let me know if I can be of help?