Noise after 35MPH

[nando2323]

I have a hum or whine almost, that happens when I hit the gas after 35MPH. Anyone know what this might be? If I am coasting I don't hear anything at all. Only when I hit the gas even slightly I hear this hum/whine noise. Truck doesn't seem to be running bad or anything at all.

 

[trail B2]

You didn't say if it has a 5 speed or auto if it has a manual see if it does it in 4th gear.That bypasses the secondary shaft.Had that happen luckily had a spare.Check the fluid in tranny transfer case rear end.

 

[nando2323]

It's an Automatic Sorry

 

[The Gat]

Rear diffrential?

 

[nando2323]

How could I tell for sure it is the rear diff. I had the fluid in it changed yesterday and it still does it. It seems to do it at 35MPH and at 70MPH and it goes away if I give it a lot of throttle. Also if it is the diff should I be worried about imminent failure then?

 

[nando2323]

By the way the truck does have bigger tires then factory one's if this means anything.

 

[The Gat]

I'm not sure what it could be. I've got the same truck as yours it seems. 109k