I just had my rear pinion seal replaced last week at a dealership in another state(had no choice). Driving home my rear end starts whining. I take it to my local dealership and they want to do the following:

 

You had your pinion seal replaced at what kind of dealership in another state and why ? was it just leaking ? did this dealership add gear oil to the rear end when they replaced the pinion seal.. ? did they inspect anything beside the seal ?

 

The mechanic probably overtorqued (likely with an impact gun) the pinion nut and cooked your bearings. Either that or you had already lost a significant amount of gear lube and they didn't refill it. My money is on overtorque. An alarming number of "mechanics" have no fundamental grasp on the hows and whys of setting up a rear end. Somehow this has always been something of a black art, but it's gotten worse in the last decade or two. It ain't rocket science but you have to know what you're doing. A good friend of mine recently got his pinion bearings screwed up by a young mechanic with an impact. In a GMC Denali quad-steer no less. I don't know what the resolution is going to be, I'm staying out of it. He's probably screwed though.

 

Had to leave it there because my overdrive gear broke and they had to fix it(my family farm is there and I was deer hunting when it broke). Anyway to tell if the pinion nut is overtorqued??

thank you both for your replies. I really appreciate it.

 

I also had a pinion seal leak develop on mine and I decided to do the job myself. The only "correct" way of doing it without dissembling the entire rear end is to mark the pinion nut, pinion shaft, and a socket with a line and count the turns to take the pinion nut off. Then replace the seal, and tighten the nut with thread-locker back to the exact same spot it was before. The reason is because there is a crush sleeve in there on the pinion shaft that is originally crushed at a specific pre-load at the factory. What the other dealer mechanic did was zap the nut back on with a impact and it crushed the sleeve more and basically screwed up the pinion gear depth and preload which is causing the whining. And even if you backed the nut off a little it would make a bunch of slop in the gears because that sleeve is crushed too far. So now the only thing that an be done is take the rear end apart to replace that crush sleeve and applicable shims then reset the pinion preload to back to where it should be.

 

If it's over-torqued the housing will get hot around the pinion snout. It's normal for them to run quite warm but you should be able to touch it. If it's hot enough that it would obviously hurt you in a prolonged contact, it's too hot which means the bearing is too tight.

I've given serious thought to opening my own axle/differential shop just because almost NO professional shops appear to know how to set up a rear end anymore. It seems they all employ methods involving the swinging of black cats and consulting ouija boards.