Posted by Ben on March 11, 04 at 15:20:02:
In Reply to: Front Differential posted by Steve G on March 11, 04 at 08:13:38:
Take a hydraulic floor jack that has good set of wheels.
With the 4x4 buttons in 2WD mode, lift one front wheel/tire off pavement. Make sure the jack wheels are in line with the direction the Sub will want to go and that there is room for it to move forward.
Start the engine and engage the tranny while holding the brake pedal. Parking brake should be set. Check that everyone/thing is clear and then let go of the brake pedal, while staying in drivers seat to manage.
It should not move, nor the front wheel spin....aka...2WD, which in a Suburban is only the two rear wheels.
If the front should spin or want to move the vehicle, the transfer case is engaged and engaged to the wheels/tires.
The front diff actuator should NOT have engaged unless the system sent power to the control line.
If the front drive shaft turns and the wheels/tires don't, then the diff actuator isn't engaged, but the transfer case is.
Best if you have lift to get all fours off pavement, but VERY DANGEROUS, but know you are engineer and understand HOW2 manage it safely.
Have found most vibration on 4x4 vehicles are from driving on pavement with 4x4 engaged. Torques all of the drive train between front and rear axles, including transfer case. Usually bent drive shaft(s) and/or U-Joints twisted...ready to fail.