I have a 99 Cherokee with 251k miles on it and the jeep runs GREAT but I have noticed a roaring noise from what seems like to me the front end of the jeep. Both front hub bearing have been replaced in the last couple months. I have also changed the fluid in both diffs and the Tcase. It does have 31x10.5r15s and I only hear the noise until around 30mph, with 20mph being the loudest. I dont know if it makes a difference but I have also noticed a shimmy in it on the highway seems like a drivetrain vibration. It doesnt matter if your on the throttle speeding up, or coasting to slow down. Any help figure out my issue would be appreciated.

 

Ujoints in axle or driveshaft

 

Would bad ujoints make a roaring noise? I could see it causing the drivetrain vibs. I do have spare out of the front of another XJ I could put in there.

 

yeah and they like to clunk at low speeds, i wouldnt replace then with used ones just get some new greasable ones and call it a day they're pretty cheap

 

Yeah especially cardon joint in driveshaft.spicer non greaseable only.thats what jeep used factory.they lasted this long didnt they.i get them local for 20-25 bucks cardon joint is more.

 

How worn are your front tires? In my experience BFG A/T's start to get noisy as they wear down past 1/3 tread left. I have the same tires and mine have been getting increasingly noisy lately. They're at about 30% tread left right now if I had to guess. From my experience having these tires on another rig they'll get louder as they wear down more as well.

Just something to be aware of. Hopefully it's something simple like tires wearing out or u-joints rather than a pinion bearing in your front diff on it's way out.

 

Well all my u joints checked out but I noticed when checking the rear d shaft that the yoke on my tcase was loose. When the PO did the hack and tap some how he got the bolt tight but the yoke was wobbling on the shaft. I pulled it off added a washer now it's tight and my driveline vibe are gone.

As for the BFGs they are about 50% but they do have some cracks in them.

 

Ck the wheel bearings again... I've seen them fail quickly from improper torque.

 

They felt good, the PO was a 15 year Mercedes Benz mechanic so I am more then certain they were installed properly and torqued to spec. It makes no noise until 20mph then it gets loud around 20mph then gets quieter from 25-30 then from 30 to 75 its not noticeable anymore due to road noise which isnt much. Im leaning towards tires but im kinda wondering if the carrier or pinion bearing are on there way out.