When I put my truck in 4hi (not sure if it does it in 4lo as well, i never use it) there is a 'tapping' noise coming from the front end. I'm not sure how to describe the sound. It is like a tapping, or a clicking. The truck shifts into 4hi fine, and it appears that everything is working. The only 'problem' I am having is the sound. I've been told that if 4x4 is working, not to worry about it, but I've found that strange noises are usually a sign of bad things.

Any help would be appreciated.

 

it's most likely a front U-joint if it only does it in 4x4. Does it sound worse when turning?

 

clicking can be front drive shaft u-joints.

put it up on 4 jack stands and run it in 4wd and crawl under it to trace the noise.
check drive shaft, CAD, differential.

also, with CAD coupled up and engine off, you can spin the wheels by hand and see if you can duplicate the noise. make sure cad is coupled or its not true test.

 

The front axle u-joints were just replaced. I'll put it on jack stands as soon as i can. I have to get some money to buy the jacks stands and a new jack. I'll post the results as soon as I do.

 

based on your description of only clicking when in 4wd, then it won't be the axle u-joints, since those turn all the time.

what is unique about 4wd is the turning of the front drive shaft, the coupling of the passenger side axle at the cad, and the power being applied through the differential, and the associated turning of the ring/pinion.

 

Sounds like your front shaft U-joints. You can pick those up cheaper than buying jackstands. If you unscrew the 4wd shifter boot, you can watch the shaft turning and hear it very clearly.

This would be the easiest way.

 

i'd rather have jackstands

 

Thank you all for your input. I appreciate your help. I will post more information when I get the jack stands.

 

He probably already has a screwdriver and chances are he don't need jackstands since he don't have them already.

Sitting under a running truck on stands is not a smart thing to do.

 

Well, I have 2 jack stands. I'm going to go home this weekend and borrow 2 from my father and have him help me with it (don't know how much help I'll need, but if I'm at his place he'll help).

And I needed to get jack stands eventually anyway, so that wasn't really a problem.

Also, would it be possible to do this without the truck running? Could I put it in neutral without starting it, put it in 4hi, and spin the front tires by hand? Or does it have to be in drive for 4x4 to work?