So i just bought this 1998 Dodge Ram 1500 Sport 5.9L with only a 124,000 miles on it and We had a full body inspection on it before we bought it and found the water pump was leaking so we fixed that right before we picked it up, then i was testing everything on the gravel roads and I put her into 4x4 and it feels like its engaged but when i get up to the 2000+ RPMS It keeps Making a clicking/Clunking noise only in 4x4. kind of like its trying to engage but feels like it already engaged i need help, someone said it might be a universal joint? but why does it only clunk while in 4x4?
Very slick truck, Its black.

 

Check the ujoints on the front drive shaft. Chances are good, the one at the front axle is bad. Shaft only turns in four wheel drive.

 

Just went through this myself. Replaced all 3 u-joints & new ball & seal in the Cardan joint and now is like it was when new in 4x4. Was a nasty clicking sound before I did this

 

Okay thanks guys and it is nasty but U joints are cheap right? the 4x4 works it just sounds bad.

 

When it gets quiet, is when you have to start worrying, that means the sloppy part has failed..... generally followed by truly hideous, expensive sounding noises.

 

Not a real expensive fix. The u-joints were around 20.00 each. The ball & seal was 30 something. I broke the H flange taking out one of the u-joints and it was only 50.00 new from a driveline shop. These were Canadian prices, so probably less for you.

 

Have a 92 that had this clunking problem. Would your 4x4 indicator light be going off and on when in 4 wheel drive? If not, then you may have bad U-joints. Do you have the central axle disconnect system (CAD)?

 

My front shaft turns in 2wd as well...but doesnt spin in sync with the rear shaft....is this a problem?

my 4x4 works fine, engages/disengages perfectly

 

They actually dont spin in sync, I was talking to these guys who both have 98 dodge rams i work with, they thought it could be these
:Accuator motor, which i dont think it is
: the differential and transfer case meet they thought it might be binding
but my conclusion after talking to dodge cause the accuator motor aint in the transfer case and the clunking i think that ive narrowed down is the transfer case. which might be worse case replacing it. but i hear it could be a chain slipping in the transfer case or theres gears in there i can replaces that the teeth might of chipped off and everytime it gets to that chipped tooth part it clunks. But transfer case is the main thing ive concluded.
====Heres a much better driving senerio.====
"Im driving over 2,000 rpms or 20 miles an hour and it clunks eveey 5-10 secs. But it isnt the same clunking noise. could be louder or quieter. then when you slow down to get to stoping speed it clunks like 5 times in a row but not at loud driving it 20."
Please help. I really need this figured out for winter up here in minnesota. Cause i will prob using it a lot. and pulling a bunch of dumb kids (friends, Family) with cars out a lot. Its my dream truck guys

 

Drop the rear driveshaft, and the tailshaft housing off the t-case, look for the snap ring that probably isn't there any more, that holds the rear output shaft in place.......