okay, here it goes...

So, i bought my D on the 7th of this month.. all was well till we had a snow storm and i had to use 4wd.. the truck started making a humming noise it would start when i would reach about 20mph and stop when i came to a stop. i first thought was it was stuck in 4x4 but, i have conformation that im in 2wd. then i noticed that this humming noise would change to a chattering when i would let off the gas. I thought with my past exp. that i could be the u-joints so i decided that since they where sorta cheap and i had a press tool that i would replace all the joints... well, no luck still have the noise... i have also checked the gear oil in both axles and they where down a little so i topped them off ran it a little to see if it might go away after the oil was added but, still no cookies..lol I have tried to pin point where the noise was coming from so i could maybe find the issue that way but, its hard to tell.. i kinda sounds like its coming from the left rear but, it also sometimes sounds like the right front... so im at a loss here so i thought i would throw it out here and see if someone might have a idea...

it's a 1998 5.2l btw

 

Well if the only thing you have messed with was the T-case then that's where the issue must be?

 

One would assume so... i have checked the fluid in the transfer case and it was full so im guessing my next step would be to see what's in there to go bad?

 

You could try and roll down a hill in neutral and T-case in neutral and see if anything changes? Then move to just the trans in neutral?

 

i'll have to try that in the morning and post back..thanks

 

okay, i tried coasting down a hill with both tranny and tcase in N... noise is still there so i went back to the top of the hill and tried coasting down with the tcase in 2wd and the tranny in N.. noise still there...so, i had a friend drive the truck while i sat in the back seat and it appears (99.9% sure) to be coming from the rear axle.. since i have no clue how the rear axle works on a dodge, whats in there to fail?? wheel bearing??

 

Put the D up on jacks and keep it in neutral. Spin the rear wheels and see if you can replicate the humming noise. Likeyou said, could be the bearing.

 

id think it almost have to be.. the u joints where already replaced.... also i dunno if i mentioned it but the noise seems to be coming from the rear drivers side..

 

Don't rule out the u-joints. You wouldn't believe how common it is for those things to already be bad when you're driving them home from the parts store.

 

I have the same humming noise in my 98 d w/ 185K 5.2 i will inform u when i get mine jacked up and diagnose problem i will check every thing u guys posted thanks. ohh i just replaced 1 front wheel bearing and 1 u joint.