Thread: 700R4 Questions

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I've got a 72 LT1 350 laying around and am thinking about finding a 700R4 to bolt on behind it.

I know there were problems with the units from the early production years, so what years should I look for if I can find one in a donor car or truck?

If I end up just buying one, which I’m a little leery of after seeing some of the posts like Don’s on his experience with TCI and seeing posts about bad luck with B&M transmissions. I was wondering who anybody recommends for a ready to run unit.

I've got an old racin' buddy here local who does automatics. Talked to him about the 700R4 I've got (reverse is out), and have almost decided to go with a 5 speed!!!! Extra work, but at least I know it's something that will hang together..... Besides, I'd hate to have people think I had suddenly become shiftless!~!!!!!!!!!!

I'm just scared of 700R4's. Replaced 2 in my 1995 Suburban in 100k miles. Kid next door had a moderate 400 and custom built R4 that grenaded 3 times. To be fair the kid was 19 and the X-wife drove the Suburban (no offense intended to the rest of womankind). But I had heard they had fundamental issues with bad castings resulting in bearing and gear case misalignment and binding. It came down to whether you got lucky or not when finding one. I never could substantiate that either though.

Feel better about them now?

Kitz

I build them all the time and don't fear them at all. They get the same inpsection and alignment checks as all of the tranny's I do. It can be a formidable piece if done right. With the LT1, it should be a happy swap.

The best years are 1987-90 these had all the upgrades the earlier ones did not, they are also non-computer stop by www.transmissioncenter.net for everything you need to make it work,the Tech people are very helpful a call to them is also a good idea.

Thanks for the input everyone. Everything is kind of in the very early planning/collecting stage right now.

Got mine from Phoenix. I agree GM transmissions have had their problems but they hold up well when beefed up. Phoenix rebuilds them to your horsepower.

http://www.phoenixtrans.com/

All the problems were with the guts ....correct????
If so ,upgrading all the internals for performance use would eliminate the problems...............??????
I have one I am considering rebuilding and converting it to manual.

Some reading is available on www.bowtieoverdrives.com

I decided to give it a shot myself. I figured I've rebuilt numerous engines over the years, I should be able to do this. There was a good article in 4 x 4 magazine where they bought a video on the tear down and rebuild, and bought the Haynes auto transmission rebuild manual for additional reference. Theirs came out with no problems. The parts are not expensive. Here's a link to a good parts supplier and the video:http://transmissioncenter.net/stock_...build_kits.htm http://www.technicalvideos.com/video...smission.phtml
I figure every guy who ever rebuilt a transmission had to learn how to do it, so why can't I? Wish me luck, I'll let you know how it comes out.

Originally Posted by nitrowarrior

I build them all the time and don't fear them at all. They get the same inpsection and alignment checks as all of the tranny's I do. It can be a formidable piece if done right. With the LT1, it should be a happy swap.

So, how much does it cost to have one built that will stand up to 450 horse, 475 torque????

$135.0

I have to lengthen message to 10 or more letters so plus shipping, insurance and handling

Good luck ............................

Might work for Grandma .............

Kitz

Originally Posted by jerry clayton

$135.0

I have to lengthen message to 10 or more letters so plus shipping, insurance and handling

I've got an injected big block and a 700 r4 and it handles the power all right. I figure I'm in the neighborhood of 450hp for sure. Had a couple problems but nothing major. It's a built unit (less than $2000 CDN) and I don't take it easy on it by any means.