My ford expedition squeaks while driving - 1999 Ford Expedition

If you have a rear drive line shaft (tail shaft) check the u-joints for a rust streak around the cross and cups. They u- joint goes dry and will squeak as the joint goes through the angle of drive. If you have a front shaft as well check it also. If they feel loose and show signs of rust have them replaced specifying joints with a grease nipple. If not that check the suspension rubbers or if you have neoprene or plastic bushes check them also for wear