The problem:
Under normal acceleration the tranny shifts OK from 2nd to 3rd. But under hard acceleration (@3500 RPM on 2nd) the tranny slips, the RPMs go to 4200, and then it engages.

Troubleshooting:
I have checked all over the Internet for troubleshooting, problem history and rebuilding.http://sethirdgen.org/tranny.htm
Many resources indicate that the 3-4 clutch on 700R4 trannys do have a history of failure.

Now what?
I have been thinking about getting the tranny rebuilt but some say it doesn't last and they end up buying a new one. I don't think this is a DIY job. So what options are there? We are talking about $900 - $1200 or more for a new one, $500 - $800 for rebuilding.

Thanks,
Ozzy

 

You can do it yourself, you can pick up a rebuild kit for around 300. BUT it requires some special tools, If you look around on the net though people have figured out work arounds for them. A rebuild should last as long or longer though, so don't worry about that. Just use a reputable shop that will install all the components that have been upgraded over the years, most of them will, and will do a shift kit as well. Mine was 1500 including being pulled, rebuilt to performance specs, 2500 stall converter, and reinstalled.

 

Actually for a number of reasons it is not uncommon for the typical rebuild to not last as long as the original. I can go into tedious detail if you like but in other words, unless you correct the common causes of complaints and failures it will be back regardless of who does it.

I prefer to upgrade to the 4L60E 3-4 pack since it is a real winner but even that won't last unless the control system problems are corrected. IMO this requires the installation of either the TransGo Shift Kit or Reprogramming Kit. If it is pushed I would also use the TransGo Hi Rev Release Springs and their Hi Rev Pump Ring Kit.

It is no more common for the 3-4's to fail than it is for the Band or the Forwards but it does seem in Hi-Po app's that the 3-4's show up more than the average 700 failure.

 

Thanks for the info. Are there any books, sites or anything out there on how-to. I have never ventured into trannys but at least I can try. If all else fails I will just take it to the shop and pay to get the work done.
I will get the shift kit once I get it rebuit.
I have read somewhere about the Corvette Servo not being a good thing for the 700R4. Any comments?

Thanks.

 

The Corvette servo will work out fine if you do not go to big on the 2nd gear feed hole, and work with the accumulator setup like Trans-Go does. B&M, Art Carr, Superior, etc. do not address this problem, only aggravate it.

 

Thanks, I will keep that in mind.

 

>Pro Built Automatics: The Corvette servo will work out fine if you do not go to big on the 2nd gear feed hole
What size do you recommend with the TransGo shift kit?

I would have thought you had to make the hole bigger since the larger piston will reqire more oil to tighten the band?

TransGo give a range for each hole, is it ok to use middle range or are there certain things to concider?