Shifting problem '06 6 speed m 3500
 

My shift sticks in gear and will not come out of gear while the engine is running. Stop the engine and put in gear when the engine starts the truck starts to move with the clutch pushed to the floor. It will fix itself if left alone and is subject to happen at any time. I replaced the master/slave cylinder kit and the same problem. When the system works it is very smooth. Could this have something to do with the electrical system because the master/slave cylinder kit has an electrical plug that plugs into a unit on the door's kick pannell.

If you have new hydraulics, my guess would be you have a mechanical issue with the clutch itself.

sounds like air is still in the system

If you still have the factory clutch/dual mass flywheel you could have a problem in the self-adjusting ramps in the pressure plate. On occasion, without warning, mine would give me a rock-hard pedal without releasing. After pumping the pedal several times it would release. I had the POS replaced a couple of weeks ago with a South Bend CON OFE with a solid-flywheel conversion, with the hydraulic upgrade kit. No slippage, good pedal feel. Just make sure the mechanic doesn't rip the shift tower boot doing the job---it's pricey!