Differential makes grinding noise, had it checked out, was told to replace whole axle, cannot do so because gear ratio is not on axle housing. need to find gear ratio

most four wheel drives do not spin both front tires other wise you would hop around corners,that being said you should be able to stop the spinning side tire by holding it in place ,do this before the tire starts spinning ,then the other side should spin.if not you have a problem start with the axle and work your way back in the drive train,simple process of elimination..the grinding noise sounds like a broken gear tooth in the tranny.requires tear down and replace gear.take it to a professional.hope this helps

That sounds very bad, Jorge. Don't drive it any more until you can either get the differential rebuilt or get the axle replaced with another good axle with the same gear ratio.

hi i had the same it was my four drive case

make sure the axle joint didn't fail then on the pass side of the car behind the axle there is a cover that houses the differential open that and check the gears in there

Remove the cover on the rear axle Inside you will see the differential gears. If the gears are damaged or there is a large amount of metal flakes in the lube, likely the differential has failed. Generally it is far cheaper and easier to replace it with a scrapyard unit. Replacing the gear set is not a bolt in procedure and takes special tools and knowledge..To replace it end to end, all you need is a decent set of tools, some common sense and a manual if you are a novice or unsure of yourself. Only thing you need is to match the gear ratio to the front one. You can either identify that from a metal tag on the cover or by counting teeth on the ring gear and pinion gears. Ring divided by pinion=ratio.
If the transfer case has been diagnosed as bad, make sure the noise isn't being transmitted through the driveshaft. Verify diff condition by looking!!

Sounds like your rear diff is winding up. possibly rear diff /or transfer box fault .

Hard to say exactly from here. However, The u-joints usually start to squeak before going bad. Park it on a level surface in a safe place and make sure it can't roll. Put it in neutral and crawl under it. Twist the shaft a little to see it there's play in the back. Might be safer to just get the rear end up on jack stands. If it's a "grinding" noise that gets worse under deceleration it's probably the rear. Also check the inside of the rear tires to see it there's moisture (gear oil) from an axle seal leaking, and/or bad axle bearing. There's an option tag either in the center glove compartment, or on the passenger's side door that will give you the axle ratio. "G" code, Like GU$, GU6,GT5, etc.

The rear diff. turns the rear wheels. It is located in the middle of the rear axle. It won't last long if you ignore it. May just need dearing's but if it is driven the cog wheels will grind to dust or drop off this can cause the rear axle to seize up and can be a danger because the back wheels will lock up. If you are going to fix it yourself let me know and I will be able to guide you through the process

To determine gear ratio, divide the number of teeth on the ring gear by the number of teeth on the pinion gear. The total is expressed as a ratio: example # total= 3, ratio is 3 to 1. On a 4x4, this number must exactly match the ratio of the differential you are not changing.
In reality any differential can be installed in any vehicle providing that the ratios are correct. To install a complete axle assembly that was not made for the specific vehicle you have requires careful measurements regarding position of the differential yoke in realation to the driveshaft output on a transmission or transfer case, proper standing angle as well as length of axles and axle tubes. All can be modified to fit as necessary but the process is expensive. Typically, you can find a similar unit for your vehicle and match the ratio stamped on a tag found on the diff cover, but to avoid problems, always count the gear teeth and follow my instructions.

call jeep and give them last 9 digits of your vin and ask for three things -Differential Type,Gear ratio, and Track lock- They will give you
1) Dana 35 or 44
2) Gear Ratio 3.31 or 3.73
3) Track Lock - yes/no