I can't really seem to find much definitive info on this anywhere.

How hard is it to replace the pinion bearings? How do I know if they're bad to begin with?

The jeep whines, loudly, around 45 mph while giving her gas. She's silent while coasting. I've been told this is the pinion bearings going out. The last time I was in there (8 months ago) there were no metal shavings in the diff.

And idears, or would I be better off taking her to a shop?

Also, is this a job that could be done with a shop manual? Haynes, or whatever other ones there are

 

Somebody correct me if I'm wrong, but I think that one is a little tough, with the new bearing the pinion ends up contacting the ring gear differently. Dealing with the shims on the carriage is best left for the pros. Suppose a guy might get lucky. There is a "crush" washer between the bearings. You torque it to crush that until the rotational friction, "preload", (measured in in./lbs), falls in range. You go. I'll wait here!

 

Bite the bullet and take her to a shop. Got it. Is this a dealership only job?

 

You're better off having a shop do this repair, it involves a few expensive special tools to do the job right. Things like a 20 ton press, pinion depth measuring fixtures, and the knowledge of how to do the job correctly don't come cheap.

 

Any idea what this would run me?

 

No idea what having it gone through might cost.
I'd start with talking to my regular shop and parts guys. Maybe call the dealer...as reference. Myself, I'd be checking the wreckers. Probably come home with some better springs and some extra drums as well.

Sure would be nice to see some play in it, a leak, getting hot....something that really says that's the problem. The smell, that can defiantly tell you.
A dry U-joint will sometimes screech rhythmically, make vibration when it's worse. Can't say I've had one do a loud wine, but then I would have changed it back when it was just chirping.
You might pull the cover and take, (another), good look at the oil, see if it smells burnt.

There's two more bearings for the carriage, as well as the pinion.

 

So, if i understand you correctly, the fluid will smell burnt if the bearing is going? Obviously metal shavings are a clear give away.

I'm going to replace the axle shaft bearings first, since those are cheap and easy. I'm also going to replace the ujoints since they havent been replaced...ever...woops.I'm also going to take the CB antenna mount and antenna off as it has made noise is the past, but different from what im hearing now.

Ill start there, but I'm just preparing myself for worst-case scenario type of deal.

The thing that is really getting me is it isnt constant. It changes pitch with speed, and it's only under power. When im coasting, she's silent.

 

Well, gear oil, (manual tranny, or differential), gets a characteristic "reek" when it's burnt. A bearing that's just starting to go might not be that hot...yet. A wheel bearing would be more likely to change sound when you are going around curves.
Yea, I'd want to rule out the U-joints. Probably not your issue but something to look at. Course my antenna doesn't normally know if I have my foot in it or not. You might pull the cover while you have the drive shaft out, maybe even jack up a wheel. Use a bar to try to wiggle the carriage, feel the pinion for play. Rotate things and look for play. Maybe something will stand out. I would check the oil level before I pulled the cover. You might check/top off your T-Case while your under there.....VV http://www.ebay.com/itm/CENTRAL-HYDR...item1c22b96618 VV

 

You can probaly look forward to about 800 bucks depending on what all needs to be replaced. A 20 ton press will cost you about 6000 bucks.

 

I thought all gear oil stunk, didn't realize it could get worse lol

Thanks for the pointers, I'll start from there.

And I actually have access to several presses. A friend works in a shop, and I'm still good friends with my shop teacher from high school.

 

Well there you go. Thought about just swapping the axle with one from the boneyard?

 

That thought has definitely crossed my mind. Problem would be finding another Chrysler 8.25 that isn't beat to hell. Most of the yards are pretty well picked over in my area and I don't wanna downgrade to a turdy-five