Vibration noise

Hello everyone,

Still chasing this vibration noise and that come when either coasting downhill or when just let go of the gas pedal. Here’s a link for the video of the noise.

https://youtube.com/shorts/buYH1z7XS8s?feature=share

 

I've got something similar although my noise is higher pitched.

If its in gear and I coast, its making noise, if I take out of gear it goes away...

 

In the trade that is referred to as reverse power flow, that is the weight of the truck driving the drive-line. If she is an automatic, put her in neutral, if manual, push in the clutch. By doing this you are taking the driven load off the 3rd member. If it goes away it is something in the axle assembly, if it is still there then it is in the driveshaft/transmission. Either way the fix is usually beyond a driveway repair for the average guy.

 

It’s not a constant noise it’s only either when I let go of gas pedal or holding speed on a down hill.

 

take the fill plug out of the third member first, then drain the lube and see if it sparkles. There are times where the fill plug wont come out and if you drain the lube then you cant replace it.

 

Probably the pinion bearing. There are 2 bearings. One side is loaded during acceleration. The other is loaded during declaration. It's easiest to tell on the freeway when you are coasting or just barely getting on the gas.