Hello all!
I'm usually at the Corvette forum, but I see there is more 700r4 expertise here. (I'm installing a 1987 700r4 in a 1980 vette).
My question is regarding the TransGo servo mod. It tells you to discard the 2nd piston snap ring, but then my band binds.
If I use the snap ring and the spacer included in the kit I get the correct band clearance. Is it ok to use the snap ring?

 

Your band shouldn't bind, if it does it means you have too many spacer washers in place of the spring. It wouldn't hurt to put the snap ring back on but I think the problem is too many spacer washers.

 

You are instructed to check to see if the driveshaft will turn in both directions. If it won't, as Jay said you have to loosen the adjustment. I also do not like that 'solid' setup that the kit instructs you to use. It makes for rough downshifts and under the right circumstances you can easily loose traction, and thus control if you manually downshift allot. Just a warning.

 

Thanks a lot guys!!
Even without the shim my band binds if I omit the snap ring.
(The springs are pushing out the spring-cover and reducing the clearance)
I test the slack by wiggling the band as told in the manual.

transfixleo: What do you mean by "solid" setup?

Spacer plate drilling of hole F (3-2 highspeed?) is specified .070-.073. Since we are metric over here I only have .059 and .079 drills. Can I use any of these?

I'm also a bit confused over the different type of kits. On the box is says SK 700-D but the instruction sheet says SK 700-G. Do I have the correct kit for my car?

 

Sorry, I was assuming that you had a Reprogramming Kit. You have a Shift Kit. The -G designation is the level code. The kits have changed over the years as they have gotten more refined. The "solid" setup is what is used in the Reprogramming Kit Servo, which means that they eliminated the inner cushion springs. I like the setup yours has better. You will not have the problem I mentioned. As to band clearance, sometimes it is necessary to grind a little bit off of the Servo pin on the band end. Just do a little and slightly round it if it is too tight. Then start with the tighter set up (just in case you took too much off) and remove what you need to get it right. Try turning the Driveshaft and see if it will turn in both directions. If it will you are OK. As to the 3-2 hole, do you have access to a numbered drill bit set? That will have what you need. If absolutely not, then I would go with the .079" but then take one of the checkballs and set it on the new hole and tap it once or twice lightly with a small hammer to close it back down a little. You should be about right now.

 

Thanks again transfixleo!!

I just run into another question: I had the checkball 10 (TV-exhaust). This is not shown in the kit, shall I leave it out?

 

I always gring about 1/16" of the servo pin when removing the snap ring, and don't install any spacers. Only install the spacers if you ground too much off the pin. Leave the tv exhaust checkball out. It's the larger check ball.

 

Thanks AlienTranz!! Do you know why they leave out the snap ring?

 

It gives a better 1-2 part throttle shift (smoother), while still retaining the same WOT throttle feel.

 

The checkball is optional. It has been known to seal off when it is not supposed to and this causes max throttle shifts and pressure at all times as a failsafe. As long as you are confident about your adjustment and would be awayre if it all of a sudden started shifting early and soft (broken cable) then it is no problem. I leave them out.

 

Thanks!!
It's to late for the servo, but I left out the exhaust ball.
Just completed my mods (.500" boost, corvette servo and TransGo SK700) and did a pressure test. (In park in the garage, its snowing heavily over here right now...)

The pressure was 71psi (idle TV) and 163 psi (full TV).
Before it was 57 and 140, with the original boost valve. (.391")
Seems to me that these pressures are on the low side, is my pump shot? What's normal with the .500 valve?