I have a '95 K2500 with a 6.5l turbo that I have had for about 18 months. When the engine is under load (plowing snow, pulling large boat,etc), or at high rpm's standing still, the engine exhausts large amounts of black smoke. I am suspicious that the turbo is not working (no turbo spooling on acceleration). Removed the air inlet to the turbo, started the engine and the turbine was not spinning until the engine was reved.I live at 9500 feet above see level in Colorado and the air temp was about 40 degrees. Inspected the waste gate and it appears to move in both directions, is closed at idle and has great vacuum at the actuator. The turbine spins by hand, with slight resistance (with the engine off). Oil has been changed on a regular basis by myself (every 3 months, around 400 miles). Using 15W-40 Carquest fleet oil. It has 92K miles, IP has been replaced within the last 10K. I have no way to check for boost at this time. Could I have a bad turbo?

you can replace the center cartridge for about $300 and a bearing kit is $90 if you can fix what you have'

If it doesn't spin freely, it is wearing on the shaft and the sooner you fix it the better.

That sucker should spin freely at idle, no stiffness whatsoever. check for shaft play by wiggling the shaft forward and back, there should be a slight bit of movement. Then wiggle it side to side, if the turbine blades touch the housing its time for a rebuild. The exhaust side of the turbo may also be damaged but thats not visible without a teardown.

Update your signature line in the user control panel so we know your ride and you wont have to repeat it.

The bearings are definitely shot and most likely the exhaust turbine on the shaft is dragging on the exhaust housing. Likely that your turbo will need a new shaft and maybe compressor wheel in addition to normal wear and tear parts like bearings and seals.

Installed new turbo and it is working so far. Got rebuilt one over the internet for $695.