We had one of the company 550s come in with blown turbo seals. The truck ran but ran like crap when we got it off the trailer. We rebuilt the turbo and replaced the oil cooler. Now the truck will only crank to a certain spot and acts like its hitting something. Stuck a bore scope in the injector bores and all the pistons look good and looks like nothing has hit them. What else can I check before pulling the oil pan?