So I was driving my truck around today without the radio on and I heard this whine when I let off of the gas when I was going like 55mph. Once I hit the gas it went away. It wasn't too loud and it doesn't do it when I'm driving around town. I never heard it before because I usually have the radio on. Any help? thanks.

 

i believe my truck is doing the same thing. or about the same thing at least. mine sounds like it is coming from the speakers almost. now that i think about it it could be a vacuum line maybe?.. im not sure either hopefully someone has the answer for us.

 

Sounds like rear diff.
Pinion bearings most likely.

 

Rabbler you could be right. Mine turned out to be the carrier bearing. Plus a few years ago I had a whine when it shifted into O/D. that problem became a transmission problem. The O/D bearing/bearings were letting go.

BlKnt18. When driving turn the O/D Off and see if the noise goes away. If it does, it's in the transmission, if it doesn't, look towards the rear end for a problem. But please let a pro check this out.
Good Luck

Kayakman
98 QC 360V8
3:55 axle - 191,00 kilometers

 

No I tried that so it must be the diff. Thanks. I want to upgrade to 410s in the future right now I have 3.55 w/ factory limited slip

 

My dad purchased a new 77 dodge and they did not fill the rear diff. It sounded like this when coatsing eaaaarrr-ear-ear eeeeeaarr. When he found out, it was too late, but he filled up the rear diff(so they did not think it was something he did)and took it in under warranty.

It did it at all speeds. I was with him watching him stick his finger in that diff hole and there was no oil in it at all.

 

damn 9.25's, mine has been holding up pretty good considering that I beat the hell out of it

 

Mine been making a slight whine for years. It hasn't gotten any louder so I'm not too concerned yet.
I've repaired so many over the years I tune it to it real quick when I hear any diff noise.
Checking the fluid is a good idea though.
To the original poster, any idea when the fluid was changed last (if ever)?

 

Ya idk when it was changed or if ever. I just bought the truck a couple of months ago.