Noisy Jeep When Accelerating

I own a rear-wheel-drive 1999 Jeep Grand Cherokee. I recently had both rear axle seals and bearings replaced. At the same time I had the mechanic check U-joints, shocks, etc. The noise from the failing bearings is gone, but now I have a loud “howl” that gets louder the more I accelerate. If I take my foot off the accelerator, the sound is gone. As soon as I accelerate, the sound returns. It is barely noticeable at speeds less than 35 mph, but the howl gets increasingly louder as the speed increases.

I returned to the mechanic the same day I picked up the Jeep. We went on a road test and I was given a story about gears in the differential and that despite the noise everything was mechanically sound. Even though the sound was not present before the seals and bearings were replaced, the mechanic assured me that nothing is wrong. This howling is giving me a headache! Can anyone suggest a fix?

If your axle seals failed, causing the differential to get sufficiently low on oil to trash your axle bearings, odds are more damage than just those bearings has been done. The howl very well could have been there before you had the work done, you may have just not heard it over the bad bearings. You could now have a bad pinion bearing, excessive ring and pinion gear clearance, bad inner bearings, or anything else. You could either have your rear axle fully rebuilt, or install a used one that hasn’t leaked out all its fluid and been trashed.

There wasn’t any noise prior to fixing the bearings and seals. The bearing noise was just a “whisper,” but I new what it was and fixed it early. The “howl” is new since I had the seals and bearings replaced… and it gets louder as the speed increases. I will check for wear. I am simply perplexed in why the sound appeared the day after I had the Jeep fixed.