Hi. I bought an 97 jeep cherokee classic 4.0 Sometimes when I put the jeep in reverse it will grind for a second and stop, but the other day I had it in part time trying to reverse out of a parking lot with kind of a slope nothing to bad and it didn't wanna move, it would move a little but it just kept grinding any help would be great.

 

its not actually a grinding noise. When i put it in reverse i feel it engage it will move when i let off the break but when i give it gas it doesn't move any faster but when i put the jeep in four wheel low it moves a little faster but it feels like something is stuck like something isnt engaged all the way please help