Oh, and yes, the growl starts around 35 to 40.

 

With luck it's only the hub bearings. Of course it could be both sides.
After I bought my ZJ, it was making a similar noise. I had it looked at by a friend. (Should have done that first). It had bad hub bearings on both sides, and in the rear D44a axle it had bad pinion bearings, bad carrier bearings, worn/damaged ring & pinion gears, and bad wheel bearings. It was my first 4WD vehicle, so I had no idea what I was looking at, except that it looked to be in mint condition, and ran great. Oh well, I loved, it so I spent the money and had it fixed.
He said the damage was probably caused by a bad pinion seal, and letting the axle run low on fluid. Make sure the fluid is at the level of the fill plug on the diff cover.

 

As long as its front bearings, I'm ok with that. I can do front hub swaps in my sleep. Rear wheel bearings will really **** me off.

 

A shop went through the rear axle for me and replaced everything. My son did the front hubs as I was sick at the time.

 

I could probably do rear bearings as long as the inner seals are still good. I just don't have the proper tools to pull the outer seals and the bearings and reseat them correctly. Plus, I paid $250 for this thing. I'm most concerned about screwed pinion or gears than anything.

I have someone who plays with these things coming by today to road test it and see if he can tell me what's going on.

 

I've never messed with rebuilding axles because I didn't know how. I didn't mind paying for the knowledge/experience so it would be done right the first time.
Now engines, that's a different topic.

 

That's what's killing me. I can tear that 4.0 apart and put it back together blind folded. And I love that motor. Its a beast and you have to be trying hard to kill it. But when it comes to rears, I have no skills with setting gears and getting the lash correct and all that mess. But I also can't afford to put out the cash to have it professionally rebuilt either.

Thought maybe I could buy some time just swapping the rear out, but it seems that bit me in the *** this time.

 

Sounds like me. I feel bad for you, but I'm sure you'll get satisfaction from that place.
On my ZJ I didn't consider swapping rears until after the shop had rebuilt my axle and I came on this site. Then I found out I could have installed a Ford 8.8" axle cheaper than they charged me for rebuilding the D44a. I knew very little about Jeeps before joining this site.

 

At this point, I'm actually considering keeping my old axle and having it rebuilt. Core charge is only $50 anyway.

 

I found a few places where I could've gotten a rebuilt rear for $450. With all the time and aggravation and gas and tools I have into this, I should've just done that to begin with.

 

So I pulled the diff cover, cleaned the mating surfaces, cleaned out the bottom of the pumkin. No metal shavings or pieces whatsoever, but the fluid was low and black as night. I resealed the diff cover and replaced the diff oil. Did the slow figure eights to get everything circulated and road tested. Seems like the growl/hum is gone now. I am still getting a knock under the front end, and still have that pull to the right, but the rear finally seems right.

Now I need to figure out what's going on in the front. I know the shocks are shot, and the alignment is most likely out because of the **** to the left in the steering wheel. I jacked it up and did the wheel rock (up and down, and left to right) and both seem solid. However, when I spin the wheel back and forth (rotate) with the steering wheel lock engaged, I can hear a "clunking" when it hits the stop.

 

Does it have CV joints or u-joints at the hubs? Can you tell their condition?
Have you checked the front diff fluid level/condition?

 

It has boots, so it is CV. The boots look in tact, so I have to pull the boot to inspect the CV.

I might use the NTB trick to see what's wrong under there.

 

What is the NTB trick?

 

Take it to NTB for a front end alignment. They see what's wrong, write up this ridiculous estimate, you tell them you can't afford that, they take it off the lift and you drive away with a list of things that needs to be fixed.