DII 04 rear humming noise @ 40-50

[Thecoffeeman]

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.

Any thoughts?

[jhdylan]

Well, Did yo check the fluid levels in the rear diff? Also what is the state of your front prop shaft. New, rebuilt, old and dying...How about the rear roto-flex have you checked that for cracks or dry rot.

[Thecoffeeman]

New prop shaft and root-flex. Haven't checked diff fluid yet, it's raining. Will check that tomorrow.

[cnfowler]

Checking the diff fluid would be the first thing to do. Hopefully it isn't the sound of your rear diff on its way out.


Colin

[Thecoffeeman]

Thanks hope not either. Reduced tire pressure for the time being, take some of the load off. Sound wasn't nearly as bad. I'll post conclusion tomorrow.

[Disco Mike]

How many miles on the truck, have you ever changed your fuel pump?
Have someone ride in the back to rule out the pump. What about your rear hubs???

[cnfowler]

How does reducing the tire pressure "take some of the load off"? Reduced tire pressures require more effort to roll, thereby requiring more force to keep them rolling. Increasing the tire pressure would require less force to roll.


Colin