The last time I went racing I had a pretty big problem with my tranny. I have a 3500 lockup vigilante along wit 3.90 gears and a rebuilt transmission with a pro built rebuild kit said to withstand 550 hp. The combo has maybe 2000 miles on it and maybe 20 passes. What I noticed is when I shift from 2-3 there is a heft delay between the 2 to 3 shift. But on the streets at part throttle it shifts perfect, its only at WOT it does this. Any ideas?

 

You said Pro Built kit, but who actually built it? What RPM are you turning to, and has the line pressure been verified? Was the servo pin length correctly checked?

 

I shift it at 6200. I had it rebuilt at AAMCO, and they were very knowledgeable about the 700 r4.

 

i didn't have very good luck with my pro built shift kit...



this happened after about 3k miles...

 

It's the shift kit/servos fault that the servo/retaining ring was seat fully and loaded sideways cracking the case? - Sorry man, I've never personally dealt with Dana from Pro-built, but that failure had nothing to do with any shift kit.

 

I won't argue that there maybe an AAMCO out there that has a decent tech, but all that I have ever encountered were lucky to even properly identify a transmission. Getting any chain store/run-of-the-mill trans rebuilder to actuallyl replace the apply piston seals and bushings almost requires a miracle.

A true 6200 w/o the dual slider spring will allow pressure fluctuation. Do you know what year trans and/or that it has at least the 10-vane pump? If it's a 7, even with the springs you'll have issues north of 5500.

 

NO it was in there the right way, I don't think that it was anything in the kit, my dad keeps giving me crap that it was the shift kit but i really didn't think that that is it cause so many people have bought and installed them without problems. I don't know what happened yet. I talked to dana and he said he has seen it before but the case already had a crack before it happened, mine did not.

 

its a 88 trans

 

skiroulertx447 - you are correct in assuming the shift kit/servo did not cause the case lip to crack like that. Whether or not it was cracked before, if the servo was in correctly, then the failue was bond to happen at some point. Few castings are even remotely close to perfect.

joeblue83 - an '88 era trans should be a 10-vane pump OE. Whether or not it has the better/dual pump spring(s) or not and whether or not the builder truely did everything I do not konw.

 

I can suggest a possiblity as to why this occurred. Her in Northeast Pa, road salt is common. After 10 years of exposure, the retaing ring gets rusty, and the groove it seats in oxidizes. I have some units that look fine at first glance, but need alot of work with a dull screwdriver and sandpaper to restore the groove and ring. If yours had something similar happen, when it was re-installed (retaing ring) it may not have been seated well in the groove, and was riding on the high spots of the oxidation in the case groove. This would cause high point loading, rather then the pressure being evenly distributed around the perimeter of the ring and groove.
Just a thought.

 

The car is form california and has never been driven in the salt. So it still looks like new underneath, no corrosion on the tranny.
I did clean the spot where the ring went in before i installed it. I think what happened is that maybe it got damaged when removing it or because it was just old, there was no visible damage when installing it. I was very careful when working on it. I will know more when i pull the tranny.

I talked to a local performace transmission shop and they said that this is a common problem on the 700r4's. They said they usually just recase it, i will probably just buy another 700 and and just use it the way it is though, maybe just install the vette servo and hope that one doesn't break

 

Your odds of a problem on a different case should be near zero. I have done over 400 of these, and have yet to see the failure you had. If your local guy says it is common, I can't relate. Not at all common on the units I do, or receive as cores.
Transgo does eliminate the accumulation spring on the servo pin, and replaces it with selective washers to allow for custom pin setting. I never use them, as it seems like a mickey mouse way to go about it. I use the factory white spring with the conical blue vette booster spring, and I custom size a GM wide band pin.
I wonder if locking out that accumulator with the spacers caused it? Either way, I no longer mod the servo as transgo recommends.

 

I've never had a case fail there either, thats only the second time I can remember seeing it on-line.

I have only done one Transgo kit, I usually run the Superior stuff.