TH350 help.

[lthomp72]

My 72 GMC 1500 has a TH350. I just rebuilt the TH350 with a TCI kit and installed a new "boss hog" stock stall torque converter. I got about 120 miles on it and it just starts screeching making other ugly noises in R and D, stopped with my foot on the brake, engine idling. It has a slight hesitation to accelrate and then accelerates and drive fine. I pulled the trans out and when I pulled the torque converter off, there were metal shavings all over the input shaft and the fluid coming out of the converter was filled with shavings. When I got enough fluid out of the converter, I could see where the tapered end of the outer part of the input shaft was rubbing away at the inside of the hub inside the torque converter. The pictures show the end of the shaft and down into the torque converter, where it was rubbing. What could have caused this? Any ideas? Anybody seen this before? I appreciate your ideas.

[GMCJOE]

My thoughts on it is you probably didn't get the torque converter seated all the way. Supposed install it based on rotation's clockwise and counter clockwise while seating the converter, according to the old man that was teaching the transmission class about 10 years ago in my Vo-Tech school. I am no transmission guy, so hopefully you can get the right answer.

[haminator]

It looks like the converter may be a lock up converter. where is the input shaft to the trans?

[lthomp72]

GMCJOE: It sure seemed to seat all the way, and once it was installed, the TC could move back and forth when unbolted from the flexplate about 3/8 of and inch, back and forth.

haminator: I was wondering that. How can I tell the difference between and lock up and non-lock up? The pump is removed from the transmission in that picture, so the input shaft is still in the trans.

Thank all for the help.

[haminator]

The smaller shaft will have a small smooth nub sticking out of the end that engages in the torque converter. If I recall the splined shafts are different sizes between the lock up and non lock-up. I'm not even sure you can even get a lockup converter to go a non lock up shaft. It just looked like there was an extra hole in the converter where that nub would fit. All of my converters have oil in them and I cant tell what it is suppsoed to look like.

[68K30]

Lock-up stator support splines, the large ones on the pump are shorter than the non lock-up.

[lthomp72]

Problem Solved: Turns out the new torque converter needed to be shimmed away from the flexplate because it had more than the allowable 3/16" movement. I tore the entire trans down, cleaned everything, installed the original torque converter, and now everything is fine. Thanks to those who offered help.

[jocko]

thanks for the follow-up, I've never heard of shimming between the fp and tc, that's good to know.