Well, I got to enjoy the new engine for all of about 40 miles. I was going to make a run into town today...car fires up on the 1st revolution, solid oil pressure...everything is good. I start backing out towards the road, got about 40 feet, something starts knocking like crazy, the car quites moving, then everything starts vibrating like crazy, and the engine dies. WTF??? It starts back up, still have solid oil pressure, so I didn't spin any bearings or throw a rod, but it is vibrating badly and I have no forward or reverse. This tranny is brand new...after it was built it was installed behind the new 388 (the first time) and has less than 200 miles total on it. It was a full on performance build...hardened sprag and race, extra hi-performance clutches, trans-go shift kit, 24,000 gvw tranny cooler in line with the factory radiator cooler, and some other internal mods that I don't remember. The convertor was also new...a ATI 10" street master. The tranny has never had any real load on it...the car has had nothing but street tires on it and they spin with any real throttle input.
For this thing to be vibrating like it is, and instantly no forward or reverse, makes me think the convertor died. What do you think?

Ok, just checking...... you do have fluid in the tranny, right? I mean, it was sitting while the engine was out. Did the fluid leak out? Mine did that when I had my engine out for about a year being rebuilt. I think the seals dried up and caused a leak. Then when I put the engine back in, the trans would not engage any gears. Once we rolled the car out of the garage, we saw the puddle of fluid on the floor.