Dana 60 “whirring” noise on Deceleration??

[69CHARGERMD]

70 Challenger. Dana 60. 4:10s. Less than a year old. No issues accelerating at cruise or laying into it. Hear and feel a metallic whirring sensation/Sound on deceleration as you come off the gas.
From what I have researched the concern might be a pinion bearing failure or poor pinion bearing preload??
Anyone agree ?
I have little to no knowledge on setting up the lash, preload, etc.
Any downside to re-torquing or tightening down the pinion bolt ?
Thx for any constructive comments.
Doug

 

[Chryco Psycho]

Great looking Chall !
if it is quiet under power it is highly unlikely the pinion nut is loose , they usually torque to 200+ Ft Lbs generally it is a bad set up between the gear mesh & you would need special tools to set it up correctly & if it is making noise the gear set may never be quiet again after being run incorrectly set up

 

[69CHARGERMD]

Thank you for the response. Less than 50-100 miles on the current gears. Had them installed not long ago. So I guess having the mesh pattern checked is the next step ?
Would a bad pinion angle do anything like this ? Ie, make the whirring type noise on deceleration?

 

[Rapidfire]

I would pull the the gear set out of the housing and put some gear marking compound on. See what the wear pattern is and adjust accordingly. Sounds to me like there is too much heel contact on the coast side of the ring gear, hence the noise on deceleration. Only two adjustments you can make is the Pinion mounting distance and Ring gear backlash.

 

[69CHARGERMD]

I would pull the the gear set out of the housing and put some gear marking compound on. See what the wear pattern is and adjust accordingly. Sounds to me like there is too much heel contact on the coast side of the ring gear, hence the noise on deceleration. Only two adjustments you can make is the Pinion mounting distance and Ring gear backlash.

Thanks for the response.
Going to have it looked at and see what the mesh pattern looks like.

 

[dgargan]

This is going to sound too easy, but don’t overlook the u-joint. I had this exact same scenario happen on a new set of gears that I had a shop setup for me. I was back in their shop a few months later with the same gripe. It was a quiet when I’m accelerating but when I let off, the deceleration was noisy and I could feel it in the car. They swapped out the rear u-joint and the problem disappeared. I felt like the u-joint was too new to be an issue, and it HAD to be the ring and pinion gears not getting along, but it ended up being that simple.