i have a jeep grand cherokee 2000 limited ..y would it now make a...

[sandler999]

...cranking sound when i back up going right?? i have had it with me on an island for the past few months and i drive it on the beach all the time.. could this maybe be from salt or sand?

 

[PedroS]

bad CV joint.

 

[margaritawithcrown]

Sounds to me like maybe a front joint or bearing is going out. Not all that uncommon on that vehicle. I would go with the wheel hub bearing, if it has started it is only going to get worse until you replace it. Soon it will start doing it going forward as well.