Jeep is home...now to start problem solving!

[KJ zGal]

So I brought the KJ home tonight finally since I decided I don't really want to sell it...and so begins the troubleshooting. I've linked to a video with a strange pulsating noise that I can't quite place. At first I thought it was a wheel bearing but the rate of the pulse doesn't change in time to the tire speed, but the pitch of the sound does change. It seems to be the most noticeable between 35 and 50 mph, above 60 it seems to go away or be drowned out by the muffler. Drone noise from the muffler or maybe a differential? It started doing it after I bought the car and wasn't driving it daily anymore.

http://www.youtube.com/watch?v=rkBvsLPLsbs

 

[cplchris]

hard to tell from the video, i would start with checking the tires for cupping or uneven wear, after that i would make sure they are balanced.

next i would check u-joints on the rear driveshaft, e-brakes, brake calipers (to make sure they are not hanging up at all).

i wouldn't think it is an issue in the differential, i would just start going through and doing routine maintenance and pay attention to when the noise stops.

replacing the rear wheel bearing and seals would be cheap/easy enough if all else fails.

 

[kage860]

That's in 2wd right? Sounds like there might be an exhaust leak. The higher pitched sound I would check the serpentine belt, and check all the fluid levels including differentials transmission and transfer case. Maybe the Universal joint? I never had to replace one of those.

 

[KJ zGal]

Thanks guys--Yes, this is in 2WD around 55mph. The serpentine belt is less than a month old, and the tires have about 5,000 miles on them. They were rotated for the first time a couple of months ago and were balanced as well. The brakes and rotors were also replaced in April, but I suppose after sitting for some time that could be a possibility. The exhaust pipe did break back in August when I was going through Philly and the mechanic just welded a new section of pipe overtop, so maybe it is just a noise coming from that. What would I be looking for to check the ebrake? It's never really worked right in this vehicle, I have to pull it up really far to stop it from rolling away so I've always just left it in gear lol

 

[ltd02]

Yeah, I'd be checking that ebrake. You've got rear drums since you have an 02. Mine acted much like you said where I'd have to pull the handle way up and never seemed very secure. Finally I just replaced everything back to and including the hardlines off the rear diff. Drums wheel cylinders all the hardware and shoes. If you get them adjusted properly it should work without much effort to set. I'm thinking your rears may not be set correctly if they were new in April. Those springs don't last forever. I usually just set them so the drums just slide on with little resistance. I've always made a few brisk stops in reverse after adjusting. That's the way we did it in the old days.