I have a 97 ZJ with 4L I6 and whenever I accelerate hard from a dead stop the back end shakes pretty bad. Now, I have a problem with my tranny but this isn't coming from my tranny it’s in my differential, I think. Sometimes I lose 1st gear and all I have to do is restart my car and I get it back. There’s also a bad grinding sound coming from the back when I accelerate hard. It also grinds bad if I put it into 2nd gear and accelerate, it grinds real bad. I want to take the diff cover off and see if there’s something wrong in there but I don’t want the mess. Does anybody have any ideas? Thanks

Sounds like you are going to have to get dirty and pull the cover off. One thing a bad Diff shouldnt make you loose first gear. It could very wellbe your Trans. Try jacking the Jeep with all 4 Wheels off the Ground using Jack stands. Start the Jeep and put it in drive and see if you can tell where the Noise is comming from.