Hey i was going to buy a Probuilt shift kit for my car and the servo and all that good stuff.... but when i called up my transmission guy to ask him to put it in for me he said "are u re-building the tranny?" and i was like "no why?, it shifts fine." and hes like "welll we'll just have to drop the pan and see how much metal is on it....kus if u put it in you may just waste your money" and i thought they only hadda be rebuilt when there was a problem with it .... lol.... its driving fine just needs new u-joints witch im getting done sooon.... but yea back to my original question how long do they guys last? and do u recommmend getting it rebuilt even if there is no problems? (theres about 140k miles on it)

 

I hate to say it, but the shop is right. 140k is high for these old-school automatics, and 700-R4's are known for longevity issues....although thats more prevalent on the older ones. 700's tend to overheat and die.

What he's talking about, the metal....I'm assuming the train of thought he's on, is that your clutch packs are probably fried up by now. Meaning, sooner or later, youre going to get clutch slippage. Just like slipping the clutch on a manual...same basic effect. Major lost power, and additional damage. With that many miles on it, I wouldn't say it's worth it to buy a shift kit this late in the game. Early on, shift kits can save tranny life...but on an old tranny like that...you're tempting fate for something to break.

I'd say, hold off on the rebuild, and hold off on the shift kit. Just drive it like it is...if it's shifting too soft for you, consider adjusting the TV cable. Instructions here: https://www.thirdgen.org/newdesign/tech/detent.shtml

If the TV cable is set properly, and you want to make the shifts just a TAD firmer...or you think you might have minor clutch slip, look into a bottle of Lucas transmission additive. It might be called SlipFix, but I can't really remember. But it's the only trans additive Lucas makes---dark red, in a big white bottle....thick as honey. That stuff will work wonders on a high mileage trans.

Then, drive it til it dies. Which, I suspect, will be a few months after that 355 goes in.

Good luck man. I know a shift kit sounds fun....but it's no fun installing a shift kit, and then having your overdrive crap out a week later because you hit it so hard from the shift kit that it snaps the band...

 

I've seen some last only a few thousand miles before problems set in, and some well over 200,000 miles. I had 130,000 on my untouched 700R4 before I dropped in the 355 listed in my sig. It lasted another couple of years, and around 35,000 more hard miles before I decided it was time for a shift kit and a torque converter. I played it safe, and got a performance rebuilt unit.

Regardless of make or model, autos aren't designed for much beyond 150,000. They wear, and you can't avoid that.

 

oh i c ok....how much would a rebuild cost? prob about 500 bones right? that really sux... lol... well what do you guys think about me dropping in a th350 outta a 79 blazer? my buddy is selling one i could get it cheap for like 100 bucks (he needs cash).... pretty sure it'll fit.... or am i wrong??

 

A 4WD Blazer - no. A 2WD Blazer, define "fit". Not going to be simple.

$500 would be a low-ball, get-it-working-so-I-can-sell-it rebuild.

 

Yeah...I know a guy that got his 700-R4 rebuilt locally for about $700, and his dad did construction work for the guy so he was cut a MAJOR deal. The average estimate I received when I asked around a year or so ago was $1100-$1300, for a STOCK rebuild. It's almost worth buying a whole, pre-built trans...

Like I said, my personal opinion is drive it til you NEED to fix it. It may fail soon, but then again, it may just last longer than you think.

 

A well known guy in my town does a lot of work on all kinds of cars and trucks, street rods, race cars, etc. quoted me for a rebuilt 700r4 for 1100 dollars. Thats includes taking tranny out, beefy rebuild for 450 hp or so, and put it back in. Not bad if you ask me. I am getting mine done there soon with Edge converter and my 3.27s put in. Ask around tranny shops in your area and see what they say. For a stock rebuild it should be less than a 1000 but beefing it up wouldnt hurt. Do it right.

Oh yea, I am in a similar fix. I got about 140 K on the car but am the second owner. Tranny feels fine and shifts pretty good but I think I want to rebuild it soon now so I don't have to worry. The engine is same way. runs good but has 140 K on it as far as I know. Couldnt contact original owner (bought the car at a private dealer who picked it up and sold it.) Well I want to buy a Super Ram but dont think that would be best since tranny might not hold that power increase and abuse. I really dont know what to do. I have the money but think beefing up the tranny would net good gains and be best for the car. The engine is old and super ram (Just base intake no cam or heads) would not be good for it.

 

yea i think im gonna wait for any trannny mods and just drop in my 355 with a 3000 stall... and put in that 3.27 disc brake rear im gettin and just wait for my tranny to completely fail... thanx guys....when i get my tranny done... do u think it would be alot easier just to buy one from TCI or Pro-Built?

 

Heard probuilt makes a great tranny may be the best one out there. He is very knowlegable and has great rep for service. They are a little bit more expensive but the things he does will make his trannies last longer than most. It probably easier to buy one unless you can find a trustworthy tranny shop who can rebuilt one for less than brand new. I was thinking on going with either TCI or Pro Built but decided to have it rebuild by my local shop. Everyone who knows the guy recommends him so I cant wait to get it done.