98 v6 rear axle howl.

dutchsn95 · 07-29-2009

Hello folks,... recently ive noticed a very high pitch howl or whine coming from my rear axle at about 40 mph. This noise only comes up
when taking my foot off the accelerator (automatic transmission)

Whenever the torque supplied from the engine is removed and the rear axle is being 'driven' by the rear wheels spinning it comes up.

My shop said it was probably the U-Joints or some play in the differential. Im not sure I understand whats involved in replacement of either.

Does anyone have experience with this exact same problem?

shinerstang · 07-29-2009

Have you checked your rear end fluid?

dutchsn95 · 07-30-2009

Its been in the shop for a bearing change just the other day.
With that change they had to open the differential. I can only assume they filled it back up afterwards... how would i go about
checking if its filled? do i have to open it up and refill, or is there a better way?

green4money00 · 07-30-2009

there is a fill plug on the side of the housing. remove it and the fluid should be level with the bottom of the hole

dutchsn95 · 07-31-2009

just went to the shop and had it checked. Seems the fluid levels in the rear diff. were ok. The U joint at the front of the differential also seemed ok. The mechanic said it was probably some play or worn gears in the differential itself.

I got the advice to put in a thicker oil in the differential to see if that lessened the sound. Only remedy would be to swap the entire of the differential. But to get 1 from the scrapyard will be difficult.

kshannon · 09-04-2009

I have a 92 5.0 automatic with the same noise when letting up on accelerator, after having bearings replaced in the differential. any help would be greatly appreciated

P4452 · 10-10-2009

Quote:

Originally Posted by dutchsn95

Its been in the shop for a bearing change just the other day.
With that change they had to open the differential. I can only assume they filled it back up afterwards... how would i go about
checking if its filled? do i have to open it up and refill, or is there a better way?

I hear if you don't break the bearings in properly that is the result. I don't know what causes it, but if you didn't follow the proper procedure (15 minute drive, 4+ hour cool down, 30 minute drive, 4+ hour cool down, 45 minute drive, 4+ hour cool down, done) it makes a damn loud racket.

P4452 · 10-10-2009

I thought I had failed U-joints, so I replaced them myself with top-of-the-line Duralast Golds. No change in behavior.

They would've noticed if the diff had play when they put in the bearings...