has anyone installed a vette servo in their 700R4? what does it improve and are there different installs?....ie: with stronger spring, without? thanks stan.

 

Just got my fairbanks servo in the mail today. I have to wait to get it installed next week. My friend had the same on in his 90 formula. It had a nice positive shift and over 3/4 throttle would chirp the tires. that was 4 years ago on a stock tranny and he has had no problems

 

so it just gives firmer shifts?....i got a trannie rebuild and put in a shift kit so it shifts pretty firm now...do you still recommend it? thanks

 

I wouldn't use the Corvette Servo if you already have a shift kit in the tranny. I'm was always under the impression that a corvette servo was to put into stock trannys and didn't produce as krisp of a shift as a true full shift kit.
Later, Garrett

 

but if you have a stall converter like say 2400 then i say get the servo cause the converter will kinda soften up any kind of hard shift...... they kinda work against themselves.....but with the write set up you can get a mean chirp and a stall i have a stock tranny with the corvette servo and i can get a nice chirp out of 2nd when im layin into it ........... i guess it all depends on what you have (parts wise)

 

If the guy was on the ball who did the rebuild it may already have it. GM recommends the following four items to improve shift quality on a healthy 700. The pressure reg spring(#8639164), the servo piston(#8642079), the tv boost valve(#8634940) and the servo housing(#8642110). If it was overhauled they replaced the tv boost valve, as far as the other stuff it's anybodys guess. One thing to consider is that while the 700 is a decent transmission, wheel chirping shifts will shorten it's life not to mention the rest of the drivetrain components.

 

Emphasize "if the guy was on the ball". I have a 700 tore down on my bench now from a '91 Z, and it had a "shift kit" installed, that made it a real "tire chirper". Unfortunatly, the "shift kit" consisted of spacers in place of accumulator springs. It still had the stock servo (not the vette servo), it still had the undersized Main Boost Valve (it measured like .422") etc...
Yestarday, I installed a TransGo reprogramming kit in a friends car that supposedly already had a TransGo installed. Unfortunatly, all I could find were 50¢ worth of 1/2" nuts stacked up in the accumulators and a FUBAR'd spacer plate

So if it shifts "firm" now, you might be opening a can of worms if you try and do anything else, cause you really have no idea what has already been done to it. I would say either leave it alone, or get a new spacer plate, vette servo and a transgo and start all over.

 

thanks guys! this discussion has help a lot! i'm going to hold off for now,'cause i've got a lot more mods to do..stan

 

Hey, Danno!

Are you sure about the part number for the servo housing (8642110)? I checked on gmpartsdirect.com and nothing came up for that number. Thanks!
A dealer advised that 8642110 has been superseded by 8673039.

 

That's the number I had, I'll make a note of the new number. At the time I logged it into my notes list price was $10.42 for the old #.

 

Try HpTransParts for your servo parts. You can get them alot cheaper!!!