[folivier]

Gordon back when I had my '99 the turbo went out while I was in the middle of Colorado. Not a great place to be due to the altitude and mountain passes I had to climb. Since we were on the way to Creede and inside the passes we enjoyed our time until it was time to head back. I had a loss of power on acceleration and hard pulls and lots of black smoke along with the engine overheating. I spoke with a mechanic before we drove back and he said to baby it, pull over frequently to let the engine cool down and watch the exhaust to try and minimize the black smoke. The loss of power and smoke got progressively worse but by then I was out of the mountains and just had the hills in the Texas panhandle to drive through. I made it back to the mechanic in Nacogdoches without any further damage. When I pulled in he walked to the rear of the coach and listened to the engine running and said the turbo was definitely bad. So there definitely was a different sound even though I couldn't hear it. Pulled the cover (or hose, don't remember) and when he spun it by hand we could feel the bearings were bad. I also had a leaking radiator replaced but that wasn't the cause of overheating.
You should be able to access the turbo to spin it by hand and feel what the bearings feel like if there is any play or rough feeling. Also look at the tips of the blades for any cracking or missing tips. If it fails the worse case would the blades breaking off and entering the engine. Other than that it would cause loss of power and lots of black smoke on acceleration and climbs.
Good luck!