blown up lockout and ring gear on a Dana 44?

So I finished my build and took my XJ out for a test drive. On the test drive my buddies and I ran a few miles down the road to a natural gas well site. (Basically some dirt to test things out in)

Ran it through 2WD and 4HI with the front locker engaged and disengaged. Everything seemed to be working fine. We left the hubs locked in and started to drive back home. A little while after getting on the pavement again and going in a straight line in 2WD we heard a loud bang and the front and seemed to act weird. (I think I heard a slight whining sound from the front right before the bang)

We stopped unlocked the hubs and got her home. When we took it apart the drivers side lockout had exploded and removing the diff cover showed a broken tooth on the the ring gear and the two chipped/cracked teeth on the ring gear.

Now I'm trying to figure out how the lockout and the ring gear would get damaged if the Jeep was in 2WD and the locker was unlocked... Any ideas? I'm thinking maybe something in the locker bound up for a little bit or maybe my t-case didn't disengage and something happened there?

When I searched I found that usually a hub goes or a ring gear goes, and usually someone is wheeling when it happens, not driving straight on pavement at about 35 MPH and both go at the same time.

Specs on the XJ
Front axle F-250 HPD44
-- OX locker
-- 5.38s
-- New WARN premium lockouts
-- Yukon chomoly shafts
-- Bought used with the locker and I did not take the locker apart to inspect it.

242 stock t-case
Longarm radius arm front suspension
14 bolt rear axle
-- 5.38s
-- grizzly locker
-- shaved

Did the locker "unlock"?

I know the select-ables will hang up sometimes.

Things go BOOM when that happens

did you break in the gears before you went and wheeled on them? sounds like gear teeth went then seized down the front axle on the road, putting enough stress to explode the lockout.....


either way something was amiss already to drag gear teeth off the first time out

I believe the locker unlocked but I cannot tell for sure.

The gears were the ones in the axle when I bought it. I had my buddy (a Master Tech) look at the gears, he said the wear pattern was good, and he set them back up.

I think, like you said Doug, something seized the ring gear causing all of this.

Lurch1980 said:

I believe the locker unlocked but I cannot tell for sure.

The gears were the ones in the axle when I bought it. I had my buddy (a Master Tech) look at the gears, he said the wear pattern was good, and he set them back up.

I think, like you said Doug, something seized the ring gear causing all of this.

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if he had to set them back up they may have been weak from too much lash, causing the loss of teeth, the teeth missed and locked the axle down transferring the stress to the hubs..... 5.38s are a weak gearset in a 44 by nature, if the PO let the lash get above .060 i would be uncomfortable with the amount of stress on the outer edges of the gears


could be one possible scenario....

So are you saying a part of a tooth could have broken off from basic driving causing the ring and pinion to bind? I'm just making sure I understand what your saying.

Lurch1980 said:

So are you saying a part of a tooth could have broken off from basic driving causing the ring and pinion to bind? I'm just making sure I understand what your saying.

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could be....something transmitted enough shock to the hub fuse to shatter it. If the gears were already broken it could have been them....or a wheel bearing seized, but that would have shown itself pretty quickly.


im just thinking out loud, its tough to say without laying hands on the axle

Yeah I know it's hard to diagnose without seeing it. I can post some pics tonight. Maybe of the ring gear only or does it make sense to snap a pic of anything else?

Sounds like the locker did not disengage.

i drove around for a while (street and wheeling) with my locker stuck locked on a d30 and nothing broke.

My guess is the ring gear gave first, locked the carrier, and instead of locking up both tires, the hub blew out as it was the weakest link. the other hub didnt blow because it wasnt locked, otherwise it would have. if you heard noise from the gears before it poped, perhaps heat was involved due to improper setup by your buddy.
how did the fluid look? was it empty? should have gotten about a quart and a half out of it.

The fluid was glittery so indicating some sort of metal failure ( broken teeth ) the only question in my mind now is how the pinion and ring got jammed up. I just want to try to figure that out before I go through another set of gears.

oh yeah, I still plan on posting pics. I just decided to drown my sorrows in some local micro brew after work so it will be tomorrow before the pics get out.

I bought my first XJ due to a "noise" in the rear end that was not diagnosable by Jeep techs. I picked it up for 4k, it was a 96 with 60k on it back in 02, a real steel!

I drove it for 6 months and I soon found the issue with the 8.25, someone, most likely at the factory, had dumped 7 large ball bearings into the drain-back tube between the inner/outer pinion bearings. One finally found its way between the teeth of the RG and pinion. She went BOOM!

Look for anything that might have come loose or been left in the diff that could have been picked up by the thick fluid and gotten between the teeth. Tear it down slowly and inspect everything as you go.

You will find the issue soon enough.

So I pulled it apart this morning and the OX is completely intact.

The pinion is pretty hard to turn now (175 inch pounds of preload now) so I'm thinking that the pinion bearings either had something get in them that seized them up for a little bit (probably the whining I heard right before it blew up) or maybe the bearings weren't getting enough oil?

I'm waiting on some help to make sure I can pull the pinion out slowly to see what it looks like and if any thing falls out, then I'll update again with what I found.

Found the problem.... The outer pinion bearing is seized up now.



We put 60 tons of pressure on it and tried heating it with a rose bud and it didn't move.

I think I'll have to get it machined out.

That would be the problem. Did the bearing spin in the housing? If not, your in good shape just replace the bearing after you get it off.

Well in an attempt to get it out we were using an air hammer and we could see the race was turning. I don't know if that means the housing is messed up or not..

The other thing that still bothers me is how this happened... Was the bearing faulty or not getting enough oil? That is an important question to answer.

Should there have been an oil slinger behind the head of the pinion gear? I've been told that it can sometimes be there and sometimes not. The factory put one there in a waggy LP44 another buddy has that I looked at today.

This pic is of mine.

On a HP I would think it needs the slinger. The slinger directs the oil off the RG and into the inner bearing and then through the outer bearing then drains down the return tube.

That bearing should get oil either way though.

I'm no expert on D-44's, hopefully someone who is will chime in.

xjtrailrider said:

On a HP I would think it needs the slinger. The slinger directs the oil off the RG and into the inner bearing and then through the outer bearing then drains down the return tube.

That bearing should get oil either way though.

I'm no expert on D-44's, hopefully someone who is will chime in.

Click to expand...

Yeah it really needs a slinger I think....it should last without one but without it I don't think it maintains enough oil over the entire pinion shaft to keep the outer bearing lubed

I'm curious what you mean by "reset up the gears"... If the pattern is good and they checked out fine, why did your buddy reset them up? Running a pattern check on an already installed set of gears requires nothing more than popping the cover, cleaning things up with some brake clean, and spreading some gear marking paint on... there shouldn't be any "resetting up" if they were already installed in the housing with the locker and the pattern checked out good.

Sounds like somebody put too much preload on that pinion bearing to me... Not trying to point fingers, but lots of people claim to know how to setup gears but actually make rookie mistakes like too much or too little bearing preload... yet they get away with it because the problem doesn't show up until thousands of miles down the road. You may have just been the unlucky one and had the problem right away due to a bad install by your friend, OR a bad install by the previous owner that coincidentally failed when you tried to test it out.