New noise!?

[Brian71583]

1996 Crew cab long bed dually 454/4l80 14bolt G80. 5/8 c-notch drop with Tinworks angle kit

This weekend my trucks started a new noise that I can’t place. It only does it when warmed up and can really come on suddenly. It’s actually seemed to come on after a stop, when warmed up.

The sound sounds exactly like a power steering whine but coming from the rear or possibly middle (carrier bearing?)

It is speed and load sensitive and louder on deceleration. On acceleration it’s there but quiet until around 30mph then it overpowers engine/road noise. On deceleration it gets pretty loud and will continue down below that 30mph.

Both times it’s happened it’s come on after driving for a bit and then making a stop at a store or something.

It sounds exactly like a power steering pump whine, even has that resonate hum/vibration you may feel with a power steering pump. I’m not an axle guy so I cannot think of anything back there to make that sound.

 

[Erik the Awful]

It sounds like you're on the right track. If it's before the transmission, it tracks with engine speed. If it's after the transmission it tracks with vehicle speed.

 

[Christopher1023]

sounds like it could be a driveshaft issue or a carrier bearing especially since the noise is coming from the back and changes with speed.could also be something with the rear end like loose bearings.i’d check the diff maybe something's off there

Christopher

 

[DerekTheGreat]

Have ye checked to see if your rear axle has oil and if it's leaking? If around the pinion or bottom of the backing plate(s) look wet or scummy, leak confirmed.

 

[Brian71583]

I did check the diff fluid level and its full, Fluid is obviously dark and I didn't pop the cover so I its not definitively ruled out but I did want to make sure it wasn't dry.

I talked to my transmission builder and he's going to check it out next week or the week after. I'm pretty certain the noise isn't quite that far back so its possibly carrier bearing but its seeming like front pump in the transmission. It is definitely no further forward than the transmission though. I inspected the carrier bearing and its far from new but I would never pull it on visual/movement test results

 

[Jimmy D]

If it whines while stopped also it's likely transmission.