I am looking for ideas as to what is causing an unidentified driveline noise. I put it in the advanced section because there are upgrades that could be involved. Here is the best description of the noise that I can come up with. The noise sounds like the beginning of a bad wheel bearing. It is not loud, it does not sound like metal on metal, just a light grinding type of noise. The noise is only there when you are on the gas and it is under load it also gets louder with higher speeds. No noise when revved in neutral and no noise when coasting. It has a tom woods cv driveshaft and an advanced adaptors sye. The transfer case is leaking a little, but is full of fluid as of last week and the noise has been there since I bought it. I know it isn't the tires because that would be the same whether you were on the gas or not. I am pretty sure it isn't a wheel bearing because I would expect to here it when coasting. I am thinking maybe it is coming from the rear differential or possibly the transfer case, but am not sure. Any ideas?

 

Sounds like a pinion bearing to me. You can lift the rear put it in neutral and try to move the pinion up and down. If it has play thats it.

 

yup, check pinions for play in both axles, thats the same symptoms i had when my front pinion bearings started failing. check on that quick, if the pinion bearings fail the ring & pinion gears will eat themselves real quick

 

Thanks guys I will do that real soon

 

I had the same issues you are talking about. I put the rear end up on stands and had a firend hit the gas a little so I could be under it to hear the noise. Turns out is was my rear drive shaft.

I have a HnT kit and in the CV section a good chunck of metal was broke off.

hope it helps.

 

When you're under load move the t-case shifter back and forth a little (just enough to put some load on the handle, don't shift it) and see if the noise changes . I have a similar noise that changes with minute movements of the t-case shifter. After rebuilding the t-case and the replacing the shifter linkage bushings I determined I would live with it and worry if it got any worse. It's not very loud, but noticeable when the windows are up and the interior is quiet.

 

I didn't put it on stands, but crawled back under it today. It appears that the drive shaft has some play in it. One of the u-joints in the double cardigan might be bad. I will have to pull it to check it out for sure.