truck developed a humming noise beginning at around 40-50 and is less noticable at higher speeds. I checked tire pressure and added air to both rear tires. humming noise began at 35 -50 then. I do need to get an alignment but hadn't had the problem traveling from ny to cape cod. developed once i got hear...more specifically after i put the truck in reverse on backward incline.
On the road, it accelerates fine and the humming starts at 40-50. As I gain in speed, the noise isn't as loud and doesnt change pitch or anything as i turn from left to right. As i slow down the sound get louder the closer i get to 50-45 and then disappears at 35 and under.
This is the first time I am having this problem. last thing is, I do have a slight leak in the rear diff. mech. said a seal needed to be changed but wasnt a HUGE deal now.