L31MaxExpress
I'm Awesome
The only 700r4 derived transmission I have ever had that lasted was the one that should not have. The 10/82 built unit with what the experts regard as the small weak input shaft, 27 spline converter, weak pump, poorly designed valve body, etc, etc. That thing lived 180K behind a stock 305 in the G20 van and towed trailers everywhere with the shifter in Overdrive. Then I hopped up the 305 a good bit and put 50K on it. Then I put a 350 making about 400 hp into it and it lived another 50K. When it finally went, it took a planet set out of it. Its replacement built off a 1992 unit, by a very reputable performance 700r4 builder lasted 20K and died again after about 15K just outside of its warranty period. I threw the 700r4 in the scrap bin and put a nicely built 60E in it from another well regarded performance builder which lasted about the same. Then there is the 97 that ate the OE GM unit in 38K and again in 40K after being built by a different builder. Both shreded hard parts. My buddy with the TPI Firebird went through 3 different 700r4 builds from 2 different builders in about 25K miles as well. We ended up putting a TH400 in that car. I had another buddy early in my OBD2 tuning stage that wanted all the torque management removed. He finally convinced me to do it because he had a "500 hp" built 4L60E in his 97 behind a 350 with efans, shorty headers, exhaust and tuning. Lets just say it did not make it 10K before it became all neutrals. My brothers stock 4.3L S10 nuked one. The 305 in the Tahoe smoked 1st gear of all things in it. There is a big reason I have so much of a sour taste for them, I have R&R'd more of those garbage transmissions than I have ever wanted to in my life. I will never put a penny into one again. If I ever have a vehicle with one again and it is due for a filter and fluid change it will be driven until it quits and it is getting a 4L80E swap and I am 100% not kidding. With the luck I have had with them I could throw together a Powerglide, TH350 or TH400 in my garage, swap it in and save money overall for the life of the vehicle losing overdrive for a more reliable transmission. I think I would rather have a Turboglide, SlimJim or Rotohydramatic or even a Dodge 42LE to anything 700r4 derived. Literally a Metric 250 would hold up better than most of them.I'm on my third TH700, the second two were rebuilt by an age-old and well-regarded local trans shop.
Both failed transmissions had broken planetaries.
Engine was essentially-stock 5.7L.
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