2009 chevy 2500 frt diff will not engage - Silverado 2500HD Chevrolet Cars & Trucks

Replace the solenoid switch on the front diff.

Well Sure it is. Disconnect the plug, remove the actuator, use a pair of pliers/ screwdriver and place it any gear you wont. But this is always getting under the truck to swap gears.

There is a shift motor on the unit that uses an electric heater coil to cause liquid to expand and shift it in and out. The motor is bad.

there is a actuator that engages the 4x4. needs either replaced or check connections for corrosion. will will see it, only thing that a set of wires runs to on your differential

There would also be a 4WD switch on diff

gas? diesel? if its a 6.0 gas they have problems with the crank sensor. check for fuel pressure and spark. read the computer codes. probably crank sensor or fuel pump

acuator at transfer case or at frt diff if acuator is moving then axles to wheels should be turning and you may have a hub locking problem. if axles to wheels dont turn then the acuator tofront diff is no good not strong enough or bent shaft on acuator, some of these use a small shaft in front of actuator also make sure if this truck use this shaft check it for wear, lift truck remove actuator push inside arm in see if wheels spin turn frt shaft while holding arm in wheel should turn is they do, replace actuator, if they dont turn then diff problem,

control module behind the passenger side kick panel

There isn't a torque spec since those bearing are pre-loaded. You place the unit on a good known vic and get a breaker bar and you might even have to put an extention on that and you begin to tighten unitil you fell the bearing start to load...a little extra short turn wouldn't hurt at that point.

i still think that you need to look at the frt drive shaft assembly, i am not saying that you may still have a front diff problem but the problem that you are stating happens only when you have all four wheel locked in correct. pulling the frt diff cover is simple, you will be able to check the fluid condation and do visual inspection, but do not forget the transfer case and frt drive shaft trun the frt diff good luck