TJ Rubicon Front Axle Gear Noise

Posted this on JeepForum, but that place is so busy it quickly gets shuffled to page 2 or 3...



I'll try to explain this as best I can...



I was wheeling Sunday and got in a deep ravine (dry). I engaged both
lockers before going in and think both locker lights were solid, but
can't honestly recall positive confirmation of that. I didn't make it
out on the first try, so I backed up to try to get a different line,
bulldozing with my rear bumper/spare. Suddenly, a horrible
breaking/grinding noise came from the front axle and the passenger side
was not turning. I stopped immediately and got out to assess the damage.



I saw no physical damage to the axle shafts/u-joints, which did not
excite me. I put it in 2wd and winched out so I could get on flat
ground. Jacked up one side and tried to diagnose the problem and
couldn't find anything. I let it down and put it back in 4wd and engaged
the lockers. There was a brief gear grinding noise in the front similar
to earlier, then it stopped. I drove forward a little and all was OK. I
drove in reverse a little and the front locker light started flashing
like it was not locked. A couple more forward and backs and the locker
lights stayed solid the whole time and no more noise from the front
axle. I took it through a mild trail just to see what would happen and
it performed normally, with no noise and drove home 10 miles in 2HI with
no noise.



So, did my locker just disengage, or was not fully locked before I
entered the ravine? Did I truly break something? I think I'm going to
pull the diff cover and axle shafts this weekend just to inspect
everything. What should I expect to find?



Thanks,
Richard

Sounds like the locker didn't engage properly! You'll probably find shavings, as long as you don't find chunks you should be ok. While you are in there flip the switch and you should hear and possiably see it engage. The magnetic coil may be failing?!?

sounds like you coulda broke a shaft??? or chipped a tooth on the ring gear possibly. I'd pull the diff cover and check the fuild for chunks of metal.

hopefully it was just the locker disengaging / not engaging correctly with no damage done to anything.

good luck. let us know.

Kinda sounds like a shaft.

sounds like a shaft to me

lonestar rubi wrote:

Sounds like the locker didn't engage properly! You'll probably find shavings, as long as you don't find chunks you should be ok. While you are in there flip the switch and you should hear and possiably see it engage. The magnetic coil may be failing?!?

TJ's don't have e-lockers, they're air actuated, so no magnetic coil to go bad. he thing I would fear is a chipped gear tooth since you had it under load on the coast side of the gear set. Only way to find out is to get the cover off and take a look.

I took the advice of a guy on another forum and decided to see if I could determine if the axle shaft(s) were broke by putting it in 4L, locked and in Park and see if I could rotate the axles. I actually had trouble getting the T-case in 4L, it wouldn't go in, then didn't want to go back to 2H, either. I think this is a different, fairly common problem. I finally got it in 4L and flipped the locker switch. The front indicator was solid right away and the rear was flashing. I rolled forward and the rear changed to solid. I put it in reverse and the front indicator started flashing again, very similar to how it acted Sunday after the grinding noise.

Once I got it in 4L and locked, I jacked up one side at a time and attempted to rotate the tires. Each one would only rotate the expected 5 degrees or so.

I pulled forward, still locked and on concrete/asphalt, and turned to the left and right until I could feel it begin to bind up, to verify it was locked, but that could have been primarily from the rear.

Next, I put it back in 2H and took a slow spin around the block. When turning left I could hear a clunking noise from the right-front. I then tested turning right and could still hear it, but not as much. I pulled back in the driveway and found the right outer stub shaft yoke is stretched to the point that the u-joint can flop around.

Now what?

new shafts are your best bet. are you running the stock shafts or chromolies? if they are chomo, they should have a warranty. I'd start there. if $$ is an issue, you could look for a set of used stock shafts or go to the dealer / 4wheel parts / etc for a stock stub shaft. Then change out the u-joint too. you might as well pull both shafts to make sure they aren't twisted. no sense in getting a new stub shaft if the spline are twisted. I say if you got the $$ go with chromoly shafts and keep your stock ones as spares.



I would still pull the front cover and make sure everything looks ok. good excuse to change your diff fluid.

Popped the diff cover this afternoon... Found chunks of spider gear laying in the bottom. Jeep wants about 1200 for a replacement locker, screw that.

Guess I'll be switching it over to an Aussie as soon as I can scrape together the cash for the parts. May be a good time to go chromo, too, but that's just more $$$.

Anybody want to buy some chit? I'm trying to decide what will be going up for sale... Maybe pistols, an old buffalo bill 30-30, shotgun reloading equipment, maybe some woodworking tools? Maybe even a 160 gallon aquarium? You never know. I'll post in the forsale section when I decide, or shoot me a pm if your looking for something in those categories.

Thanks to everyone for their advice.