Obnoxious driveline noise

Hey guys,
I have a 2000 XJ with about 167x miles and about 6 months ago I noticed an annoying chirping like sound that has only gotten worse over time. It seems to be its worst at low speeds, but I can also hear it at cruising speed. It is rotational in nature, as the jeep moves faster and faster the chirping sound gets worse and at a stop there is no noise. Same in reverse as in drive. When I first start driving it doesn't happen until after around 10 miles of driving at which point it doesn't go away. No noticeable difference in drivability. The noise seems to worse when cruising, much less noticeable with the gas applied. No change to the chirping as the brake is applied. Noise sounds like it's coming from the front end.

Jeep has a 4.5" lift, SYE with Adam's driveshaft and I have already replaced all the u joints, brake pads and shoes (not rotors), ball joints and around 2 years ago I re-geared the front and rear and put a Truetrac in the front. The only improvement I noticed was from rebuilding the rear driveshaft, and it just took longer for the chirping to return didn't eliminate it.

My next suspects are wheel bearings (which are 4 year old Timkens), possible warped rotors or sticky caliper. I haven't noticed any burning smell or pulling which makes me a little skeptical of the issues being brake related.

I was wondering if any of you have had a similar issue or have better diagnostic techniques besides trying to listen to it. I'll keep working it any advise of any updates.

Finally if this is the wrong place for this thread sorry for being the new kid.

Hello and welcome, have you thought of the front pump bearing in the transmission? I had an 01 XJ with an annoying noise like you're describing that happened after I changed the fluid over to full synthetic AMSOIL. I had to put in an additive for the noise to calm down. Outside of that have you checked the backing plates behind the front rotors to see if you picked up a rock that could cause a similar noise.

Da XJ nut said:

Hello and welcome, have you thought of the front pump bearing in the transmission? I had an 01 XJ with an annoying noise like you're describing that happened after I changed the fluid over to full synthetic AMSOIL. I had to put in an additive for the noise to calm down. Outside of that have you checked the backing plates behind the front rotors to see if you picked up a rock that could cause a similar noise.

Click to expand...

I can't say whether that caused a issue or not, but I've been running Amsoil for 21yrs now in my 2000!

RCP Phx said:

I can't say whether that caused a issue or not, but I've been running Amsoil for 21yrs now in my 2000!

Click to expand...

I think that my front pump bearing was just going out anyway, that 01 XJ was my wives to drive full time. It was also only 2wd. I didn't mean to sound like I was blaming AMSOIL, they have fantastic products

I hadn't thought of that I appreciate the input! What additive did you use? I may try to add some to see if I get any improvement that would further point me in that direction.

The backing plates are both off of the rotors so that wouldn't be an issue.

I used a BG brand additive from a Quick Lube. Was a transmission conditioner if I remember correctly.