'69 C/10 Stalling Issues - TorqueConverter?

[clarlee]

I've been working on a 1969 Chevy C/10 with a LG 250 engine and a THM350 automatic Trans. I'm having issues with it stalling out while driving. I can hit the gas and go, but when it gets to about 40-45 ish MPH, it starts dragging (almost feels like your downshifting) and will eventually stall if you don't let off the gas and slow down a bit. If you slow down to about 30-35 MPH you can hit the gas again up to the same 40-45 MPH and the same thing happens all over again. Just to get more info, I took it to a nice straight downhill grade and can get it to accelerate to more than 45 when going downhill.

It has also been wanting to stall while slowing/stopping. Note, I can throw it in reverse/neutral/park and haven't been able to get it to stall, I'm only having these issues going forward. It also doesn't matter if I'm in drive or 2nd. This problem is definitely speed related and not engine RPM related.

I am assuming that it's a bad torque converter. I am not noticing any odd sounds, vibrations or other weird things coming from the motor/trans, so I don't think the problem is there, but I'm more of an engine guy, I don't know as much about transmissions.

Any ideas would be greatly appreciated. I've already pulled the trans out. I'm not against buying a new TC, but I don't want to if that's not going to fix the problem.

I first posted about this here:
http://www.hotrodders.com/forum/69-c-10-stalling-issues-torqueconverter-234944.html
It has some discussion already. May help...

Thanks in advance