front differential groan?

[izackary]

Last night I was driving in the pouring rain and since my tires are almost completely bald, put the truck into 4WD a coupole times. Each time, though, there was a definate groaning sound coming from the front end whenever it was engaged. I almost want to call it a grinding sound. I can feel vibration back thru to my feet. I'm running stock size tires, and the brown wire mod ('99 with control-trac, though I had control-trac on the whole night), and one of my front tires has a slow leak around a screw, so the pressure is about 5 psi below the other front but i hardly think that would make such a difference. I didn't get to troubleshoot much before but I'll try somemore later today, and try and pinpoint the location of the sound; whether it's the differential, or the transfer case. Also, for the record, I'm running on worn-out ball joints even though I have replacement control arms from JoshC (and have had them for several months now). Any ideas would be GREATLY appreciated.

PS: I haven't yet opened or serviced the differentials, but I also have 106k miles on the rig.

 

[Hokie]

I'm getting a differential/gear whine ish sound from mine. Can't tell what it is. Sometimes is harsh road noise then sometimes it sounds like gear whine...

 

[Nate1]

Your tires are probably a little bit different avg diameters from your fronts vs rears, so you have a difference in speed even going in straight lines, so locked in 4x4High on pavement, you are putting stress on the drivetrain, thus you can hear your TC 'groan' and 'whine'. Mine does it ocasionally too.

 

[izackary]

but because of only a 5 psi difference? hmm....i gotta run, so i'll look this up again tmw.

 

[Nate1]

No, because of uneven treadwear

 

[izackary]

It's not just occasional though. Whenever I have the front differential engaged, it acts up. If it's occasional, it's because I use 4WD only "occasionaly." I'd love to have the problem solved by this weekend before we go wheelin!