So I jacked my jeep up to rotate the tires and put one wheel stationary but locking it in place with a chaulk. On the other side I can move the tire 1/2 inch or so backward and forward. I don't think this is normal.

When I slow down I hear a little clunking sound as well. Not horrible but it makes me think the CV/U joints might need to be replaced. My grandfather said I should take the car in and have them check/adjust the rear clip to pinion. Not sure if that is what he said but he indicated that there was an adjustment point in the rear diff.

Any ideas? I am new to the world of mechanics but that is why I bought this jeep. To learn and grow my knowledge and skill set.

It is a 1999 TJ with 4.0L engine. Stock everything that I can see.

Also a question concerning undercoating/line-x and how easy is it to work on after you have this done to the bottom....

Thank you in advance for any help you can give me.

Also if you are up in the Northern Michigan area and want to talk in person I am in Traverse City. I will buy the beer.

gears in the diff

Your rear axle is likely a Dana 35c which can clunk driving over uneven areas as the axle shafts move in/out a tad which is normal. The axle shafts that the wheels are bolted to need to be able to move in/out so they can be shoved in enough to remove the c-clips inside that holds the axle shafts in place. Being able to rotate a tire somewhat when the other is chocked so it can't move is also normal due to a bit of normal (required) slop between the gears.

^^^ x2...

Thanks guys! Hopefully it is nothing then.