D44 Diff/gear Rust

This is my first foray into diff country, so forgive me if I sound clueless.

I knew this rear diff (54 CJ, rear, d44) had some water in it but I'd drained it , put some oil in it and set it to one side till I could get to it.

Before I start in, my question is; how much damage is too much? I'm certain I'll have to replace the gearing in it because it's pitted pretty good. I'm also certain I'd have to replace the bearings and I guess shims as well, but I'm wondering about the actual diff case. Can it be cleaned out, sandblasted, whatever? There's a lot of good DIY info to see how to do the work, but I'm trying to figure out whether I've got a rebuild in front of me or a basket case.

Here are a couple of pictures, any advice is appreciated.

 

Has it been welded? Turn it so the spider gears are showing. Show us the face of the ring gear, close in. These shots are positioned to tell us as little as possible.

Did you run it with fresh oil in it before you took it apart? Was it noisy? The rust on the edge of the ring gear would not concern me.

 

It wasn't run after the oil was put in, but (and I didn't mention this before) the pinion is wobbling pretty good and the seal was drooling hard so that's going to need to be taken care of regardless.

 

The front diff on my '70 cj5 looked like this when I drained the milkshake out of it.


I refilled it with fresh oil. That was seven years ago and it has had no problems. Yours looks way better.

The milkshake:

 

What ratio is it? The tapered 44 is not a very desirable axle. And this is an open axle too, which is even less desirable. I would try to find a replacement, or I'd put a new outer pinion bearing in it and run it. Nothing to lose...

 

It's easiest to do when you've got it out on the bench. But I'll be honest, I've run gears that look a *hell* of a lot worse than those. Aside from the pinion seal and bearings, which you're obviously going to need to fix, I'd clean up what you've got, and run it, unless the carrier bearings are wasted.

 

Running front rusty pitted gears is a different animal than running rear which is loaded all the time. I’d tear it down, clean everything up, and see what you’ve got. Post up pics after cleanup. A wire wheel on a drill can do a lot to clean gears up that you would think are trash.

 

Yeah, I wouldn't have even opened it up if the pinion wasn't wobbling.

I'm not really worried about the desirability of the axle, i'm mostly interested in the function. I live in Florida so basically I just need this thing to drive out on the trails. I might consider getting a locker for the rear though.

And if the carrier bearings are wasted? Are they that big of a deal if I'm already in it for the pinion bearing?

 

No, they're not a huge deal. Being as it's had water in it, it might not be a bad idea to just plan on replacing them as a matter of course.

 

Ok. Cool. I'm going to clean up the gears and see how they look. A last question regarding removing the carrier. I saw at least one example of a guy using bars to pull the carrier rather than a spreader. What's the general consensus on that? Savvy and frugal? Or dumb and damaging? If it's not dumb, is it just a mallet to.bang it back into place? I appreciate any guidance. This is where I'm learning.

 

I haven't personally ever used any special tools to pull or install these. It's probably *easier* with the tools, but they're not strictly necessary, as far as I'm concerned.

 

I would point out - these bearings do not come for free. I expect you could spend a couple-few hundred dollars on a used replacement in better condition and be ahead in money terms. Worth investigating.

 

If this is a trail vehicle i'ld do your best to learn the process on the frugal side.

My carrier came out easy enough, like a calf with a seasoned cow. Just catch it before it hits the ground.

 

This. I always work over a thick rubber mat, because when you're prying it out of there (small bar behind a ring gear bolt), it will drop when you're not ready. Also, I would just order an install kit, (bearings, shims, marking compound, seal, nut). You're going to need it all.

 

The differential case appears to have been thru at least one rough rodeo already.
And who knows the quality of that rebuild...or the one before.
I would suggest complete tear down and inspection, as already mentioned.
You need to see what you have to work with before proceeding.
At that time, you can rebuild the axle assembly or replace it.
If the tapered shafts are Dana marked, and not bent or twisted, I'd keep them as off shore replacement axles are junk.
Don't go cheap on axle build; it will cost you more in the long run.
Do it once, and do it right.

 

Another that would be rebuilding or, more likely, replacing it. Yes, trail use only would put limited mileage on it. But that is the worst possible place to have it fail.

 

So um... After I pulled my axles the diff actually rolled out with no pulling. It literally rolled out of the housing with no friction.and uh... Shouldn't there be shims? I'm starting to think this thing is a write off.

 

There might be shims. It's not very *likely* that it's going to pattern worth a damn with no shims, but it's not outside the realm of possibility that that's how that gearset wanted to be setup to get a good pattern.

 

The shims are behind the bearings, may not be easy to see.

 

I might have a line on some axles out of a 1970 CJ. I'd like to stay out of swaps that require grinders and welders, any thoughts on how these might fit?