I test drove a 88 cherokee xj. As i was driving on pavement (30 mph) I heard a low pitch noise. not a grinding or winning noise coming from what i think is the front drive area. It was not the tires.

It does have a rusty 3 inch lift on it. with pretty bald bfg 30" tires.

should this be a concern? Any ideas what it could be?

thanks