Hey guys, I found this site when I typed my truck problem into Google, and I saw so many posts that pertained to my truck. I liked what I saw, so I registered instantly. I have a 2000 Ford F150 7700 Edition (rare find) with a 5.4L motor and 3/4 ton rear end, transmission, frame, and axles. I've had it for two months now, and I've noticed some sort of vibration in the rear end while I'm driving. It occurs MOSTLY when I'm climbing a hill and my my transmission hasn't shifted to OD yet. I have Terra-Grappler 285's instead of the stock 245's, but I'm worried that my rear end or perhaps my transmission could be the problem. Any advice??

 

bearings might be shot in the rear axle seals unbalenced drive shaft unbalenced tire could all be a factor, also maybe ring or pinion are loose in the rear end and arent torqued to spec