Rear diff whine on deceleration on K2500HD

[Spoolmak]

While on a trip away with the camper on and 1000 miles from home, my pinion seal started leaking badly. I decided to get it replaced at a private repair facility that was recommended by the RV Park we stayed at. They were very helpful, got me in right away, and replaced the seal. The shop looked professional and I was very happy with the equipment in the facility, the mechanics, and the service I got. But from that moment on when I decelerate, the rear end has a high pitched whine. I suspect the torque on the pinion input shaft nut is not what it should be????

Any thoughts will be appreciated. If that's what it is, I assume the fix is to unbolt the driveshaft, remove the 'donut' (which is apparently easier said than done), loosen the nut and then torque it to specs?????

I will take it by the dealership to have them set it up properly, but would appreciate hearing from some of you much more knowledgeable people before I do.

Thanks in advance for your thoughts.
Tor

[JohnC]

Sounds like the pinion depth changed. IIRC, the procedure is to mark the nit relative tot he shaft and replace the nut in exactly the same place as removed, i.e. same number of turns, not torque.

Yes, the crush sleeve will have to be replaced.

The longer you drive it the less likely the noise will ever go away... (no matter what you do.)

[Spoolmak]

Thanks, JohnC.

I've booked the truck to go into the dealership next week for them to 'fix' the problem. They said the same thing you did, so I feel reasonably comfortable about the repair, although they cautioned me saying it could be more.....

I'll let you know what happened.

Take care,

Tor

[Spoolmak]

Got the truck back today after repair at dealership. Turns out the pinion bearings were damaged. There was .020 backlash play (ideal is .007). the tech could move pinion fore and aft. A check of the gear contact pattern indicated pinion bearings play. Disassembly of diff then found worn bearings. These bearings and crush sleeve were replaced and backlash adjusted for proper gear contact pattern.

The noise is gone and she is really smooth.

The damage to the wallet is extensive. $503 in parts (gasket, Bearing assembly, Seal, Bearing, Spacer-dr, nut, gear lube); the labor was 6.7 hours at $110 per hour for a total of $733; with taxes the bottom line was $1441.43. Ouch!!!!

When I got home my wife smiled and said, "Honey, it's only money. Now we don't have to worry about it breaking down on us on one of our long holiday road trips."

I feel better already!

Tor

[JohnC]

Sounds like the first shop didn't tighten the nut enough. Maybe they couldn't count turns...

Anyhow, the pinion bearings need to run under a pretty serious preload or failure is quick. Good thing you caught it before it got worse. Having the pinion run out of alignment like that can be destructive in short order.

[Spoolmak]

Sounds like the first shop didn't tighten the nut enough. Maybe they couldn't count turns....

Yeah, that's what the tech said too. If that nut had been tightened another 1/4 turn the first time, I would have $1441.43 more in my bank account today.

It's history now.

Take care,

Tor