M915A1 problems

My M915A1 has some blue/white smoke coming out of the stack what would be some possible causes and is this ok to drive? Also M915A1 does not downshift very well is there some adjustment that can be made to fix this?

Thanks,
Bryan

Blue smoke means burning oil, start with the easy fixes, see if the turbocharger has oil seepage on either side. Take the truck on a hard run and see if it clears up after you check the turbocharger. Make sure you don't have oil dilution. On the Allison, check the modulator cable and the linkage to the gas pedal, make sure everything is working freely.

Whats it smell like, oil or fuel? The smoke, not the transmission....

How does the engine run? Any skipping or knocking and is there any pressure when you take the radiator cap off? We have a truck at the shop with a blown head gasket that runs good but put out more white smoke/steam than a fog machine!! Also have a Deere excavator that when the fuel filter is getting clogged it will start missing and pumping out blueish smoke.