I have owned one gen 2 4x4 2500 dodge and now a 1500 of the same year (1998) I know they have different front axles and transfercases so I would expect them to operate a little differently. When I engage the 4wd on the 1500, it is very noisy, it makes a sound that is somewhere between a whine and a grind. It gets worse as you speed up and by the time you are at 45 MPH in 4x4 it sounds like the front end is going to come apart. My 2500 never made a sound. I've searched the forums but I can not find anything relating to a sound like this that only occurs when 4wd is engaged. The truck had a new rear end put in before I purchased it but the gearing was not changed. Any Idea's or stories about strange 4wd sounds? Thanks

 

when in 4wd, the front drive shaft, pinion, ring gear, and carrier bearings are turning, whereas in 2wd, only the axles and spiders are turning.

a roaring or growling sound is probably the pinion bearing. if you jack it up and spin the yoke you might can feel it.

if you can safely put it up on 4 jack stands and operate it in gear, a short piece of pipe is a good stethoscope for tracking the noise. be very careful of moving parts.

 

i have a similar sound in my truck. but ONLY in 4x4. took it to a local shop, and found the problem. my front drive shaft cv is bad. mechanic told me the last one he had built for a chevy was $300. think i'll just limp mine for a litttle while till i can afford to fix it. hope this helps

 

I would hope that for that 300 bucks the customer got a brand new driveshaft..... the CV joints on these are rebuildable, and for under a hundred bucks.....

 

I agree with HeyYou, you can fairly easily rebuild the CV for much less than 300 bucks. Best of luck.

 

I took my truck to Leonard's Off Road in Hillsboro Oregon. He's got a great shop. He took my truck for a spin and said that in his opinion the transfer case was just getting old and may need a rebuild but said it could also be the double c joint. Anybody rebuilt the double C? Does it require any tools that regular u-joints dont?

 

Its a bit more interesting, but, no. You can do it with nothing more than a chisel (to get the snap rings off), and a hammer, and a couple blocks. Beware the ball and spring in there though, those can make your life a bit exciting.