lionelbob

Hi Everyone,

Having some problems with my 1971 Cutlass, 28K miles all original. A few weeks ago, I had some transmission problems. My TH350 would get stuck in first gear after a passing-gear downshift. I took it to a particular AAMCO, as recommended by my mechanic of 15 years. The guy at AAMCO has 20 years experience.

I was hesitant to pull the all-original untouched trans, but flushes weren't working. Anyway, it turned out to be somewhat serious: a good amount of torque converter and clutch metal in the pan. So he replaced all clutches, seals, the modulator, the pump gears (pitted), and the torque converter. I just got it back, shifts wonderfully but now I have a different problem.

Here's the issue:
At idle (more pronounced in D), there is a significant "wobble" vibration. This disappears when driving (when the TC locks up), but if you shift into passing gear there is a higher-frequency and somewhat violent vibration. This occurs if you rev the engine while in Park too.

What worries me is now my transmission guy is getting a bit confused. His only recommended action now is for them to try another torque converter...under the assumption that we got a faulty one.

I know there has to be more to it than that. Could it also be the flexplate? Are the weights on the flexplate and TC adjustable? Is there anything else it could be? It feels like something is definitely out of balance.

I want to go back to him with a list of things to check & try. It's all on their dime now (good thing), but car show season is upon us and I would prefer we get this right quickly.

I don't think it could be anything else that's gone wrong, the carb was rebuilt just before the transmission problem, and was running incredibly smooth.

Thanks for the help guys!

74 Omega

This happened to me after having my TH350 rebuilt, it started as a small vibration and got worse, it was a faulty torque converter.

Shizzy

first off, your converter doesnt "lock"

I would go with his suggestion however.

compedgemarine

years ago I was at DynoTech in Detroit. they make driveshafts for NASCAR and other racers and do alot of high speed balancing. there was a big crate of torque converters there. when I asked about it it turns out that they were from Chrysler and they would not balance out on their equipment so they were sent to DynoTech to see if they could save them. they said some were so far out that they had to scrap them. long story short just because the converter is new does not mean it is balanced.
steve

lionelbob

Thanks for the advice and insight. It ended up being a faulty/unbalanced torque converter; just bad luck. Replaced and running great now!