your rebuilt turbo is fine...thank your oil filter for that!! any damage that was done before has left its mark and rebuilding the turbo was clearly a false diagnosis even though the shop that rebuilt it said it was shot. It's obvious that rebuilding it didn't remotely fix the problem so there is more to the oil burning than the turbo. a leak down test only involves the actual leak down tester and an air compressor, either of which you could *Deleted* in your parking space for an hour or 2. I still can't see the cylinders/rings being shot since it purrs like a kitten still. But you said it best, let a professional take one final look at the truck and see what his conclusion before you make any final decision on what to do with the truck.