Question:

"Sounds" like yours is working normally. The only time you will hear any shifting noise is going into 4WD-Lo. Otherwise the difference between 4WD-Auto and 4WD-Hi is handled through software. Inside the transfer case is an electromagnetically engaged clutch pack that is enganged about 5% of the time via pulses sent from the GEM computer. That computer monitors the relative speeds of the front and rear diveshafts and increases the engagement time in roughly 10% increments whenever it detects the rear going faster than the front, as in slippery situations. Switching to 4WD-Hi effectively locks the transfer case, giving 100% (or close to that) engagement of that clutch pack, and a 50/50 power distribution as you’d have in a manual transfer case. The same occurs in 4WD-Lo except additionally a reduction gear is switched in to allow much slower operation, with correspondingly multiplied torque. Since the front and rear axles are locked in either of these last 2 positions, the drivetrain cannot relieve stresses that happen in a turn (where the front is trying to go faster than the rear) unless the wheels can slip on the ground. That driveline wind-up increases until something gives or breaks, so you probably heard the tires skidding a bit in the gravel.   =Vic= Bear gap, PA – Hide quoted text — Show quoted text – > Hi Folks, > My 2000 Explorer XLS is my 1st 4wd truck and I need some advice. > In a gravel filled yard I gently exercised my 4wd hi an lo. Normally, it’s > always in auto. > 1) Should I expect to hear and shifting/locking sounds when switching between > 4wd auto, 4wd hi, and back? (I don’t). > 2) When driving slowly around a fairly tight circle in 4wd low, I could rubbing > and > a slight grinding sound. Is that typical or indicative of problems? > Thanks and regards, > Phil

Response:

Hi Folks, My 2000 Explorer XLS is my 1st 4wd truck and I need some advice. In a gravel filled yard I gently exercised my 4wd hi an lo. Normally, it’s always in auto. 1) Should I expect to hear and shifting/locking sounds when switching between 4wd auto, 4wd hi, and back? (I don’t). 2) When driving slowly around a fairly tight circle in 4wd low, I could rubbing and a slight grinding sound. Is that typical or indicative of problems? Thanks and regards, Phil

Response:

>1) Should I expect to hear and shifting/locking sounds when switching between >4wd auto, 4wd hi, and back? (I don’t).

When you go from 4wdauto to 4wdHI, you don’t hear much >2) When driving slowly around a fairly tight circle in 4wd low, I could >rubbing >and >a slight grinding sound. Is that typical or indicative of problems?

Do not make turns in 4LO.  This will damage your transfer case and axles.4LO locks up your axles to turn at the same revolution, so if you are making a turn , the inner wheels will be forced to turn at the same rate as the outer wheels, causing binding on your axles.  4Lo is only for extreme cases if you are stuck in deep snow or sand or mud that 4High cannot accomplish. You should go as straight as possible in 4LO.

Response: