Howdy,

I have been having (for a year) noise from rear end that sounds like bearings. I'm trying to target the problem. I already changed the rear differential oil and that didn't seem to make a difference.

2000 F-150 extended cab 4x4.

It is a low whirring noise goes away when I let off the gas. I’m wondering how to narrow down the possibilities.

Please steer me in the right direction.

Thanks, Barham

 

If the noise comes in between 35 and 45mph when you are barely on the gas, it is the ring and pinion gears. This is probably your case, because if it was a bearing and you had it for a year, it would be getting worse and louder. Hope this helps.

 

Not totally....I had carrier bearings going bad on me for almost the two years I first owned my 99. Not until about six months ago did it start to get worse. My noises were a constant whine, and the faster I went the faster and louder it got and it whined all down to about 15 mph. If you do some askin around, and get a few proper tools, You can do this fix within a day. Its really not that expensive. I bought, axle, inner and outer, and carrier bearings for about 250, directly from ford. Thats also including the pinion crush sleeve and pinion seal. Just make sure you do some askin, because your book may not tell you everything you need to, and if not done properly, you can do worse damage than before.

 

Thanks for the relplies. I read my post and realized I had it backwards. The sound goes away when I get off the gas unless there is still alot of stress on the drive (like steep downhill). I am only worried because I will be towing a trailer (6000Lb) occasionally starting in mid-May. I will look into the ring and pinion gears. I am probably selling the truck at the end of August. If it is the gears, is this critical or just noisy?

Barham

 

Noise on acceleration is usually aimed at the inner pinion bearing cone and cup. Noise on deacceleration = outer pinion bearing cone and cup. Noise all the time = DIFF side bearings or axle bearings. Do you see any lube leakage anywhere on the axle assembly? Lube leakage many times points to the first area to examine. If the pinion bearings are spalled or pitted, I recommend changing all bearings and seals in the axle assembly (including the crush sleeve). A quick examination of the lube may reveal many tiny, shiny, particles if one of the bearings has spalling.