A while back I pulled the 318 out of my 84 d150 because I could see the crank walking in and out 1/8" when I reved the motor. It had the trust bearing wiped out and also destroyed the trust surface on the crank. I had a fresh rebuilt 360 that I installed at that time and was hopping for more performance with the same millage. well the 360 had a oil presure problem. that I still am looking for the cause of. 80 lbs cold at 1k and 15lbs at 1k hot and thats with a HV pump it was 5lbs hot with a standard pump. I rebuilt the 318 with new crank and bearings and freshened up the heads and put it back in a couple of weeks ago. Everything seems fine so far. Now I just got a chance to pull the pan on the 360 and checked the main bearings. they all look new except the #3 thrust bearing is wiped out and the trust surface of the crank is destroyed. There is a good 1/8" groove worn on the trust surface of the crank, The "bearing" surface looks fine on the crank but the bearing is worn to the cooper.
I know that the torque converter is engaged in the trany correctly so I don't know what could be the cause of the trust bearing having so much force that it wears out in 5k miles. I'm worried that my new 318 is going to suffer the same problem. Could there be something wrong with my trany that could cause this. Its a 998 lockup that I rebuilt myself. Has about 12k on it I put a reman torque converter in at the same time. The trany performs fine and I have even towed some 10k loads with it and no problems. I just don't wnt to destroy another crank. I also need a new crank for my 360 or can the trust surface be welded up and remachined on a cast crank?

The deal is that the original 318 I pulled for the trust bearing and it had good oil pressure when pulled. Now the 360 also fried the trust bearing and the oil pressure really wasnt that bad at speed 30psi just way lower than would be normal for a new engine. All the rest of the bearings look new with no wear at all. I just think that something is pushing the crank forward hard. and yes I did have to pull the TC up to the flex plate.

Makes you wonder if the pressure regulator in the trans isn't working properly. If it's not dropping excess convertor pressure, maybe the convertor is being pushed forward with more force than what it's supposed to be.

Transmission issues can create it. If you had two motors do it with the same trans behind them then I'd be looking at the transmission.

http://www.enginebuildermag.com/Article/1957/thrust_bearing_failure.aspx

Humm. Well I remember before I pulled the first motor I could push the crank in and out over 1/8" when the motor wasn't running. So there was no static pressure that means that when running the pressure is being exerted. I wasn't aware that the converter could balloon out that much.
guess I'll have to pull the trany and check it out not sure what to check for. Maybe do some external pressure tests.