I had developed a whine in my trucks rear-end in December 2015. I read some write-ups and watched some videos on replacing the bearings in the rear end. Bought a 20-ton shop press at Harbor Freight to seat the bearings. I replaced the carrier & pinion bearings. I seem to recall the parts were about $150 or so, and I couldn't afford a mechanic's rate to fix it.

I know I faulted when I put it back together, as I could not get the pinion nut tightened all the way with my hand tools. I hit it with an electric impact wrench and left it at that, so there was a little bit of movement in my driveshaft. I drove around with it like this for 9 months. Then last week, I paid a mechanic $50 to tighten up the pinion nut for me. I should have done this right away back in December.

One week went by, and now my bearings are screaming at higher speeds. When I slow down, I hear a different, kind of lashing noise. I've parked the truck and am not driving it now. Did I destroy the bearings by leaving the pinion nut loose all that time, then having it tightened up? How do I proceed from here? Do I just replace all the bearings again, then have the mechanic tighten the pinion nut for me? Is this a job that is strictly for professionals? I don't mind opening the rear end and replacing the bearings again, it is a setback, but it appears needed. I just don't want to screw this up again. Thanks.

I called the mechanic and he said it would likely cost $600-800 to replace the bearings, or twice that if they have to put a new rear-end in the truck.

 

Most likely you have ruined the ring gear, pinion gear as well as the pinion bearings. You will most likely need a complete rebuild.

 

I would shop around some other shops. I had both axles in my Expedition regeared, with 4.10s, and completely rebuilt including the LS in the rear and the total was around 1700. East Coast Gear Supply in Raleigh did mine and I can't say enough good things about them. They are also a mail order house and can supply all the parts for you or your mechanic.