Shop that specializes in speed work recently installed a TH350 into my 83TA.

Their rebuild guy located the core and did it to TH350C spec adding shift kit and 2200 lock up converter. Also, has cooler installed.

When I picked up the car it had a bad vibration - noticable mostly at 1500 and real bad at 2500 rpm. Vibration was there when stopped in neutral / park and very noticable on the road as well.

I thought it was the converter - took it back - their tranny guy and the mechanic who did the install both drove it and spent a fair bit of time with it. They said it was not the converter but a bad misfire. No vibration was present before the car went to the shop though.

Also, when I rev the car from under the hood the engine seems smooth to me but when I rev it from inside the vibration is very noticable like in the dash, the back of the seat and maybe the transmission tunnel area.

I changed the plugs and checked the header temp at each exhaust port at around 2500 rpm- all about the same so maybe no misfire. Havn't changed the wires yet though.

The vibration gradually subsided but is still there after 600 klix since rebuild. Mainly just at 1500 and 2500 as described.

Tranny not slipping so far - it launches good and it barks into 2nd in a big way for a tired LG4 with no mods except headers.

Checked fluid when I got it back first - bright red - now, 600 klix later, it's got dark particles in it - can see it on the dipstik and on a white paper towel it's dark grey.

Sorry for the long post but I need some input as to the vibration issue and what now appears to be friction material in the fluid.

Does this sound like a converter problem that's taken the rest of the tranny out with it.

Any help greatly appreciated.

 

if you never had a miss before you took it there it'd be pretty foolish to think it developed one while they were doing the trans r&r, unless there's a leak in the vacuum line to the modulator and i doubt that.

 

I have had the exact problem, I went through every thing and the problem kept getting worse. Ended up pulling the motor and found some rubbing of the crank on the oil pan. One time the jack broke and it dented but I pulled it out and it seemed decent then but I think with time it got worse. I wish I could say for sure but I havent put the new engine in yet.

 

It was the converter - they ended up rebuilding the tranny again and installed a new converter.