02 Suburban 4X4 Output Shaft Engaged
 

Greetings, I believe I am having trouble with the transfer case on my 02 Suburban. I am hearing a clanging noise when I put it in gear and vibrations at hiway speed. Also a squeeking sound which sounds to be driveshaft/transfer case related. I put it on blocks today and did find a bad u-joint at the rear differential, but don't think this could be the whole problem.

Also noticed a little radial loosness at the rear output shaft of the transfer case.

Also noticed the output shaft to the front axle turns with the rear drive shaft. Is the front output shaft supposed to be engaged at all times, even when not in 4 wheel drive?

Any suggestion would be greatly appreciated. Thanks

20020 Suburban 1500 4X4 (180,000 mi.)

For the front driveshaft. The actuator in the transfercase engages power from the transfercase to the driveshaft when engaged, the other actuator in the front axle engages also when you switch into 4x4. If your switch is in AWD the transfercase is engaged spinning the front driveshaft but leaving the axle disengaged. Even in 2wd mode some of the spinning motion in the transfercase is transfered to the front driveshaft causing it to rotate. Bad u joints and bearings in the double cardigan joint if you have one can cause major vibration and road noise even if the vehicle is in 2wd mode.