Is my rear end going out?

LibertyCRD · **Posted:** Sun Jun 06, 2010 11:55 am

So when I bought my Jeep back in Winter, there was one morning when I backed out of the driveway, turned left, and couldn't hardly take off. The rear end acted like it was "locked up" and wouldn't hardly move. That's the only time that happened so far. But what keeps happening now is that when I turn left or right, at slow speed (such as driving through a fast food restaurant drive-thru) the Jeep will "hop" and lurch a little. Yesterday, I was towing a trailer and I could hear some "clicking" coming from the rear. Then...when I tried to back that trailer into the driveway while turning the steering wheel, there was a ratcheting and hopping coming from the rear end. You could actually hear the rear diff ratchet and pop and you could feel it in the Jeep. Almost like something in the diff. was slipping. All these symptoms are WORSE when the diff. is hot.

Under most driving conditions, things seem fine. No loud noises, and no driveability issues. It's mostly when I turn left or right, mostly when hot, and gets worse with loads.

It's the original axle, factory trak-loc, and 83,500 miles. Does it sound like I have one of the diffs. about to fail?

tommudd · **Posted:** Sun Jun 06, 2010 12:19 pm

Need to change the diff fluid and add the additive. That may help or it maybe already too late
Change the fluid and put the additive in, then drive in circles both right and left this will work the additive in good.
Since its been making noise for a while like I stated it may be too late and you've burnt it up. Worth the cost of diff fluid and the additive to try it though

LibertyCRD · **Posted:** Sun Jun 06, 2010 5:09 pm

Ok. The dealership I bought it from in Ohio said that they "went through everything and serviced all the fluids". We both know that it's hard to say what that really means. :mrgreen:

I just bought two quarts of 75-140 synthetic per the owners manual, and a bottle of LS additive. Going out to change the fluid right now and inspect the gear set...

tjkj2002 · **Posted:** Sun Jun 06, 2010 8:57 pm

LibertyCRD wrote:

Ok. The dealership I bought it from in Ohio said that they "went through everything and serviced all the fluids". We both know that it's hard to say what that really means. :mrgreen:

I just bought two quarts of 75-140 synthetic per the owners manual, and a bottle of LS additive. Going out to change the fluid right now and inspect the gear set...

Add the friction modifier 1st before the gear oil,4oz is needed.

LibertyCRD · **Posted:** Thu Jul 08, 2010 10:25 am

OK, so I drained the fluid and inspected... visually I saw nothing wrong. No metal chunks, no irregular wear on the ring or pinion teeth, spider gears look OK. I did not remove the carrier to REALLY check...just just by looking at it everything appeared normal and there was no debris in the fluid.

So I buttoned it back up, used the friction modifier and fresh synthetic fluid per the owner's manual. Been driving it for a while now and the POPPING and jerking is back!

Again, it's most noticeable at slow speed (drive-thrus, parking lots, etc.) when I'm stopped, and then let off the brake....there is a POP and the rear end wiggles. I can apply the brake, release again and POP...then the rear end wiggles. Sometimes just driving in a circle it'll pop too.

It almost feels like something is slipping...almost like teeth are unmeshing, slipping, and then meshing together again. At full highway speed there is no abnormal noise or vibration.

What the heck???

Straight6Jeff · **Posted:** Thu Jul 08, 2010 11:37 am

When you changed teh fluid, did you use a quality contact cleaner to get the old fluid out of the carrier and clutch's/steels?

Sounds like it is your LSD is tight. Could be just a tightly clutched trac-lock, or the steels could be galled. At 83k, it is probably toasted, especially if the previous owner neglected the unit.

As for the dealer, I have never heard a dealer say "we did not do a darn thing to this before we put it for sale...."

FWIW, I have found the Ford Racing Friction modifier to work the best. It provides good characteristics on slow speed tight turns, but will allow the LSD to transfer quickly when called upon.

Is my rear end going out?

Who is online