Main Thrust bearing woes
 

I posted this elsewhere I thought maybe I may have further input here.

Had an oil pressure problem all of a sudden ranging from normal to 0. As I increased rpm
"slightly" the oil pressure moved toward 0 and let off the throttle it went back to normal. I removed the oil pump and screen and found the screen clogged real bad. Checked all of the main bearings/journals and they are good and within specs. But # 3 thrust bearing on one exterior side is pratcticlly gone. Cut open oil filter and found no metal particles. But in the pan found a piece of the # 3 bearing thrust side. My guess is this happened in short order and probably the screen plugged restricted oil circulation and somehow toasted the side of the bearing. I am replacing the oil screen and pump. Of course the cranshaft end play is way out.
Note, all of the bearings at journals are good, the engine does not have any noises...knocks etc., what are the opinions if I just replace the thrust bearing and if the end thrust clearance is ok, just leave the engine as is and drive it.?
This is the original 302FI / auto trannie/overdrive, in my F150 extended cab, never had any issues with oil/pressure before. Been using Mobil 1. About 125K on engine. Plan on keeping the truck (it is like new condition in and out) and later tear it down or buy a long block when I have the time to do it. I do not drive it much these days and figure at 62 years old I dont need another one until light years away.
I have some suggest that the converter may have "ballooned" or high presssure in the trannie building up and pushing the crank forward???

The tranny/converter issue might be possible. If you replace the bearing(s) - I would personally consider replacing them all for even wear - and it's within specs afterwards, shouldn't hurt it to run it as is until you decide to put a long or short block in. I've become more accustomed to doing engine flushes - especially on higher-mileage engines - when changing "dinosaur" oil and filter to reduce blockage from sludge and build-up, etc. How long have you been using Mobil 1, and did you do a thorough engine flush prior to switching? I know Amsoil recommends using their engine flush to 'prep' the engine for using their synthetic oils.

Thanks. Does a coverter ballooning develope a noise that woul be notable?

I've never had one baloon on me, but I would suspect if that is happening, you may hear some chatter from it making contact with something in the bellhousing or on the rear of the engine block.