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Looking for a good 700R4 transmission for my '87 K-5 Blazer. I have had the one in it rebuilt 3 times over the last 10 years and it keeps losing reverse and hanging up in 1st gear. A mechanic friend suggested just replacing it with a different unit altogether, even if it needs to be rebulit.

Free shipping, but I know nothing about them.
http://racetransmissions.com/store/inde ... c=overture" onclick="window.open(this.href);return false;

Well, the tranny finally gave up the ghost this past weekend. Been running on 2 gears since January the few times it has been driven. I can't seem to find a used one anywhere around that's worth purchasing. Let me know if anybody knows where a used one can be found locally.

Thanks!!!!!

I used to have a 1988 GMC Jimmy (full-size) back when I was in high school and college. My parents owned a couple of auto parts stores and I was able to get parts on the cheap (actually I was just able to bill parts to the store and pretend to work it off). So, I naturally did what any high school kid would do and had a suspension lift installed and a set of larger wheels/tires. I proceeded to go through numerous 700R4 transmissions over the course of just a few years. We rebuilt the transmission using the best possible replacement parts and even used heavy duty items for the torque converter and other parts which should have made a difference. No luck. We even purchased a brand new one from Chevrolet. No luck. We ended up just replacing the whole thing with a Turbo 350. Worked great and the loss of overdrive was never a concern.

Not sure if there is any logic behind a suspension lift and bigger tires causing transmission failure. However, I never have had any trouble out of a TH350 and they are cheaper to build as well as easier to find. If I can't solve the problem with the 700, I will probably just look into converting over to the TH350. I am willing to give the 700R one more try though, just with a different unit before I make the decision.

Thanks for your input.

dolphinatic wrote:Not sure if there is any logic behind a suspension lift and bigger tires causing transmission failure.

The addition of larger wheels and tires just put more strain on a transmission that was already considered light duty. I originally tried just riding around in drive rather than overdrive even at highway speeds. I still had the problem of the transmission hanging in first gear or even overheating and boiling the transmission fluid. I probably should have converted to the TH350 long before but I could just not understand why the 700R4 continued to fail even considering the quality of the parts and mechanics that installed them. I know of 4 complete rebuilds during 2 years. That does not include other times when we just installed a new torque converter or undertook other repairs. I finally just purchased a new z71 around my sophomore because this truck was on the sidelines too much. The parents were not unhappy to see the GMC finally sold.

The only thing I never tried with the 700R4 was a transmission cooler.

http://www.manual-transmission.com/

Location: Headquarters in Tallahassee, Fla.

Phone: 877-626-8726 or 850-222-6993

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