Hey JKF,
I got in my jeep yesterday and turned out of my buddys driveway and hear a weird grinding/rubbing noise coming from the rear. It continued as I drove to dinner and then home. I crawled under and checked, and everything looked fine. It sounded and felt too far back to be the transfer case so I think its the diff. I have a 44 rear of course, with 3.73 and the factory lsd. It happens mostly on turns, but seems to not be nearly as bad if I let off the gas when turning. Then today, driving it, I went around a turn and the rear diff was making grinding noises horribly, and it was slipping so much that the rear tires weren't turning. I put it in 4wd and made it to school. Now I dont know what to do. I have limited experience working on my jeep. I can fix bigger stuff and have done an axle shaft u-joint but this may be a little too far advanced for me. If i pull off the diff cover to check, I feel like ill just end up having to put it back on and filling it up just to get it to a shop. Should I still check out the diff myself? Anyone have any ideas what is wrong?

 

At least pull the diff cover off to make sure. I would rather make sure my gears are grinded or good then take it to a shop for them to tell me.( plus it'll cost a lot less if you do it).

 

Sounds like your LSD is toast. Good time to regear and swap to TT or lockers.

 

If that is the case, would it be okay if I locked the rear if I plan to possibly run 37s or 38s in the future? I know the front 30 is my weak link, but would the rear 44 be fine?

 

If you go through with a regear, obviously you'll have to do both the front and the rear.

As far as being OK with a locker in the back of the Dana 44 with 37+ tires... There are so many variables, the only honest response I can give you is it depends on how hard you are on it. I have had big tires my whole life, up until I got my JK. I am shying away from the big tires if at all possible, because with big tires comes increased risk of breakage. Thus far i've had zero issues with my 33's and 2" lift, so i'm staying there until I do.

There are tons of threads and opinions on this. Make sure and do a search. Can you break something with stock tires, no lockers, and no lift? Absolutely... But the bigger you go, the more problems you create. That goes for lift and tires.

You'll need to take into consideration how far out new tires are as well, if you're considering a regear. Lots to think about.

 

Check the diff, transmission and transfer case fluid levels. Look for fluid leaks.

To diagnose a potential diff issue, USING EXTREME CAUTION!, I put the rear axle on jack stands and in 2wd have someone put the jeep in gear while I listened for the source of the problem. Listen at the diff and each wheel. Low diff fluid could cause the diff internals to grind. Grinding could also be brake/ebrake pads. Slipping could be transmission, transfer case, ring and pinion, or spider gears. Drain the diff into a clean container. Inspect the drain plug magnet. I also put a magnet in the drain container to attract filings. Any chunks or filings likely mean bigger issues in the diff.

 

Turns out the LSD in the rear was toast along with my ring and pinion. Regearing to 5.13s and getting the factory lsd replaced with a yukon duragrip posi unit. Thanks for the help guys. I did end up pulling the cover myself and found junks so I took it to the shop.