3.92 Rear End Noise

[The_Chemist]

Does anyone who has a 3.92 Rear end get any kind of high pitched noises or gear whines?

I originally had a high pitched noise from the factory at 43 - 44 mph. The Chrysler rep drove my vehicle and had the dealer replace the rear ring & pinion plus associated bearings.

After the rebuild, I now have the same 44 mph high pitched noise, but its range extends from 42 mph to 48 mph. I have also gained a similar noise at 32 mph and 70 mph. In addition now, when coming to a stop, I can hear the gears wind down, sort of like a turbo spooling down. It's so annoying.

At highway speeds I can now hear a wha wha wha wha sound from the gears.
My quiet cabin now sounds like I'm driving a 1950's pick up truck.

The rep was correct, the original high pitched noise was coming from the rear differential, but after the rebuild it is exponentially worse.

The Chrysler rep is coming back so I can ride with him and decide what to do next.

My truck has been in the shop cumulatively for around 35 days for this issue and many other factory defects.

My question: does anyone else who has a 3.92 Rear end hear any kind of high pitched noises, whines or noises in general?

Mine was whisper quiet except for the 44 mph high pitched noise before the rebuild.

Input is appreciated. Thanks.

 

[SpeedyV]

Does anyone who has a 3.92 Rear end get any kind of high pitched noises or gear whines?

I originally had a high pitched noise from the factory at 43 - 44 mph. The Chrysler rep drove my vehicle and had the dealer replace the rear ring & pinion plus associated bearings.

After the rebuild, I now have the same 44 mph high pitched noise, but its range extends from 42 mph to 48 mph. I have also gained a similar noise at 32 mph and 70 mph. In addition now, when coming to a stop, I can hear the gears wind down, sort of like a turbo spooling down. It's so annoying.

At highway speeds I can now hear a wha wha wha wha sound from the gears.
My quiet cabin now sounds like I'm driving a 1950's pick up truck.

The rep was correct, the original high pitched noise was coming from the rear differential, but after the rebuild it is exponentially worse.

The Chrysler rep is coming back so I can ride with him and decide what to do next.

My truck has been in the shop cumulatively for around 35 days for this issue and many other factory defects.

My question: does anyone else who has a 3.92 Rear end hear any kind of high pitched noises, whines or noises in general?

Mine was whisper quiet except for the 44 mph high pitched noise before the rebuild.

Input is appreciated. Thanks.

No noise whatsoever in my drivetrain.

I once experienced the sort of behavior you’re describing in another truck, but it was when I had the rear pinion seal replaced and the shop did not preload it properly. But that made a “whirring” noise at all speeds. Yours almost sounds like it’s unbalanced, creating an issue at only certain RPMs.

 

[768mph]

Does anyone who has a 3.92 Rear end get any kind of high pitched noises or gear whines?

I originally had a high pitched noise from the factory at 43 - 44 mph. The Chrysler rep drove my vehicle and had the dealer replace the rear ring & pinion plus associated bearings.

After the rebuild, I now have the same 44 mph high pitched noise, but its range extends from 42 mph to 48 mph. I have also gained a similar noise at 32 mph and 70 mph. In addition now, when coming to a stop, I can hear the gears wind down, sort of like a turbo spooling down. It's so annoying.

At highway speeds I can now hear a wha wha wha wha sound from the gears.
My quiet cabin now sounds like I'm driving a 1950's pick up truck.

The rep was correct, the original high pitched noise was coming from the rear differential, but after the rebuild it is exponentially worse.

The Chrysler rep is coming back so I can ride with him and decide what to do next.

My truck has been in the shop cumulatively for around 35 days for this issue and many other factory defects.

My question: does anyone else who has a 3.92 Rear end hear any kind of high pitched noises, whines or noises in general?

Mine was whisper quiet except for the 44 mph high pitched noise before the rebuild.

Input is appreciated. Thanks.

I had a 2016 Mustang GT premium that had a vibration and gear issue. Ford must have spent $10k trying to fix it. Replaced the driveshaft 3 times with several rebalances, replaced the half shafts, and rear diff. End result, manufacturer buy back.

Had a 2018 Charger Scat pack, similar gear noise in the rear. Changed the fluid per a TSB, and noise was nearly gone.

Sometimes it’s little things that help. Hopefully this is your fluid change and not a buyback. Good luck and keep us informed.

Also, 3.92 here and quiet as a mouse.

EDIT:
One could suggest for them to check the pinion angle? It may be off and would cause those symptoms. Adjustments and shims could fix this.

Sent from my iPhone using Tapatalk

 

[diamondmi]

Does anyone who has a 3.92 Rear end get any kind of high pitched noises or gear whines?

I originally had a high pitched noise from the factory at 43 - 44 mph. The Chrysler rep drove my vehicle and had the dealer replace the rear ring & pinion plus associated bearings.

After the rebuild, I now have the same 44 mph high pitched noise, but its range extends from 42 mph to 48 mph. I have also gained a similar noise at 32 mph and 70 mph. In addition now, when coming to a stop, I can hear the gears wind down, sort of like a turbo spooling down. It's so annoying.

At highway speeds I can now hear a wha wha wha wha sound from the gears.
My quiet cabin now sounds like I'm driving a 1950's pick up truck.

The rep was correct, the original high pitched noise was coming from the rear differential, but after the rebuild it is exponentially worse.

The Chrysler rep is coming back so I can ride with him and decide what to do next.

My truck has been in the shop cumulatively for around 35 days for this issue and many other factory defects.

My question: does anyone else who has a 3.92 Rear end hear any kind of high pitched noises, whines or noises in general?

Mine was whisper quiet except for the 44 mph high pitched noise before the rebuild.

Input is appreciated. Thanks.

Nothing on mine. Very quiet inside.


Sent from my iPhone using Tapatalk
Waiting for my newly ordered 2020 Laramie Longhorn, Delmonico Red, chrome bumpers, 20” wheels, 5.7 V8 Hemi MDS VVT eTorque, 3.92 rear, all options except diesel, multifunction tailgate, protection group and trailer tow group. Interior Black/New Saddle. Looking forward to delivery. Truck arrived!!! Yes!

 

[MJP]

Does anyone who has a 3.92 Rear end get any kind of high pitched noises or gear whines?

I originally had a high pitched noise from the factory at 43 - 44 mph. The Chrysler rep drove my vehicle and had the dealer replace the rear ring & pinion plus associated bearings.

After the rebuild, I now have the same 44 mph high pitched noise, but its range extends from 42 mph to 48 mph. I have also gained a similar noise at 32 mph and 70 mph. In addition now, when coming to a stop, I can hear the gears wind down, sort of like a turbo spooling down. It's so annoying.

At highway speeds I can now hear a wha wha wha wha sound from the gears.
My quiet cabin now sounds like I'm driving a 1950's pick up truck.

The rep was correct, the original high pitched noise was coming from the rear differential, but after the rebuild it is exponentially worse.

The Chrysler rep is coming back so I can ride with him and decide what to do next.

My truck has been in the shop cumulatively for around 35 days for this issue and many other factory defects.

My question: does anyone else who has a 3.92 Rear end hear any kind of high pitched noises, whines or noises in general?

Mine was whisper quiet except for the 44 mph high pitched noise before the rebuild.

Input is appreciated. Thanks.

Nothing noticeable with my 3.92s.

 

[The_Chemist]

I had a 2016 Mustang GT premium that had a vibration and gear issue. Ford must have spent $10k trying to fix it. Replaced the driveshaft 3 times with several rebalances, replaced the half shafts, and rear diff. End result, manufacturer buy back.

Had a 2018 Charger Scat pack, similar gear noise in the rear. Changed the fluid per a TSB, and noise was nearly gone.

Sometimes it’s little things that help. Hopefully this is your fluid change and not a buyback. Good luck and keep us informed.

Also, 3.92 here and quiet as a mouse.

EDIT:
One could suggest for them to check the pinion angle? It may be off and would cause those symptoms. Adjustments and shims could fix this.

Sent from my iPhone using Tapatalk

Thanks for your input. I really appreciate it. I believe what you are saying. I really doubt if the dealer service department is going to get the rear diff as precise as it came from the factory.

I'm going to ask that they replace the entire rear axle/differential as a factory complete unit.

Mine is just bad!

Front axle also makes loud groans and scraping noises when in 4WD Auto. We'll have to address that as well.

I do get a lot of gear whine from the rear after the rebuild now as well. My quiet truck is no longer quiet.

Thanks again!

 

[SpeedyV]

Thanks for your input. I really appreciate it. I believe what you are saying. I really doubt if the dealer service department is going to get the rear diff as precise as it came from the factory.

I'm going to ask that they replace the entire rear axle/differential as a factory complete unit.

Mine is just bad!

Front axle also makes loud groans and scraping noises when in 4WD Auto. We'll have to address that as well.

I do get a lot of gear whine from the rear after the rebuild now as well. My quiet truck is no longer quiet.

Thanks again!

Wow. Don’t they know they’re supposed to fill them with fluid?!

 

[The_Chemist]

I had a 2016 Mustang GT premium that had a vibration and gear issue. Ford must have spent $10k trying to fix it. Replaced the driveshaft 3 times with several rebalances, replaced the half shafts, and rear diff. End result, manufacturer buy back.

Had a 2018 Charger Scat pack, similar gear noise in the rear. Changed the fluid per a TSB, and noise was nearly gone.

Sometimes it’s little things that help. Hopefully this is your fluid change and not a buyback. Good luck and keep us informed.

Also, 3.92 here and quiet as a mouse.

EDIT:
One could suggest for them to check the pinion angle? It may be off and would cause those symptoms. Adjustments and shims could fix this.

Sent from my iPhone using Tapatalk

Thanks for input. I think my noise and now noises are just an anomaly to this particular axle/differential. I was really hoping they all weren't that way. That's why I started this thread. I wanted se to make sure there were good set-ups out there.

Thanks to all for input.

 

[The_Chemist]

Wow. Don’t they know they’re supposed to fill them with fluid?!

The front axle does sound low or dry to me!

 

[db682]

No noise from my rear diff but man my brakes have squealed since day one.

 

[The_Chemist]

No noise from my rear diff but man my brakes have squealed since day one.

Yeah, I have the brake squeal too. They replaced some stuff per TSB, but it didn't help.

 

[Firebird]

Mine is silent, 12,000 miles on my truck

 

[Billet1500 4x4]

Does anyone who has a 3.92 Rear end get any kind of high pitched noises or gear whines?

I originally had a high pitched noise from the factory at 43 - 44 mph. The Chrysler rep drove my vehicle and had the dealer replace the rear ring & pinion plus associated bearings.

After the rebuild, I now have the same 44 mph high pitched noise, but its range extends from 42 mph to 48 mph. I have also gained a similar noise at 32 mph and 70 mph. In addition now, when coming to a stop, I can hear the gears wind down, sort of like a turbo spooling down. It's so annoying.

At highway speeds I can now hear a wha wha wha wha sound from the gears.
My quiet cabin now sounds like I'm driving a 1950's pick up truck.

The rep was correct, the original high pitched noise was coming from the rear differential, but after the rebuild it is exponentially worse.

The Chrysler rep is coming back so I can ride with him and decide what to do next.

My truck has been in the shop cumulatively for around 35 days for this issue and many other factory defects.

My question: does anyone else who has a 3.92 Rear end hear any kind of high pitched noises, whines or noises in general?

Mine was whisper quiet except for the 44 mph high pitched noise before the rebuild.

Input is appreciated. Thanks.

Sounds like they didn't set the lash correctly. The problem with dealerships is the techs are not rear end specialists they don't work on them day in and day out and likely didn't set the rear end up correctly or the housing is slightly off which caused the original problem and is still causing the problem. Best bet without taking it to a specialist shop would be to have them replace the entire rear end housing and all with one that's fully assembled from the factory.

 

[Rob5589]

So, the 3.92 is in no way more prone to whine than anything else. If the gear set was set up wrong initially, then the shop tried to re-use it with a new set up, you can get a worse result. But lets assume the shop did indeed replace the gear set and now it is worse. A bad set-up is likely, a bad gear set less like likely, and a poorly cut housing even less likely. Although any of the above are a possibility. Generally, most techs do not specialize in differentials. Those that aren't experienced will use the markings on the gear set itself to set depth. It can work but, the better way is to set depth by what the pattern looks like based on experience. This ensures the depth is set to the cut of the housing and not the gear set when lapped.
Differential noises generally: On decel, front pinion bearing; on accel, rear pinion bearing; certain speeds/light throttle, ring and pinion; on turns, the loaded side can be carrier or axle bearings.
Your option other than the dealer is to find a competent differential shop for a test drive and inspection, if deemed necessary.
Just to qualify my statement, once upon a time I did it for a living and have set up 3000'ish differentials.

 

[The_Chemist]

Mine is silent, 12,000 miles on my truck

Thank you. I appreciate all the replies. This will help me a great deal when I return to the dealer, meet up with the Chrysler rep and try to hopefully and finally get this truck repaired correctly.

Sounds like they didn't set the lash correctly. The problem with dealerships is the techs are not rear end specialists they don't work on them day in and day out and likely didn't set the rear end up correctly or the housing is slightly off which caused the original problem and is still causing the problem. Best bet without taking it to a specialist shop would be to have them replace the entire rear end housing and all with one that's fully assembled from the factory.

I'm going to try and make that happen this time (replace the entire assembly with one directly from the factory). Hopefully Chrysler will accommodate me!

That's a good point that you brought up about the housing being out of spec. I'm sure they all get assembled with the same shins, so that could have been the original high pitched noise.

Thanks!

 

[Whupas1]

7500 miles and no noise

 

[The_Chemist]

So, the 3.92 is in no way more prone to whine than anything else. If the gear set was set up wrong initially, then the shop tried to re-use it with a new set up, you can get a worse result. But lets assume the shop did indeed replace the gear set and now it is worse. A bad set-up is likely, a bad gear set less like likely, and a poorly cut housing even less likely. Although any of the above are a possibility. Generally, most techs do not specialize in differentials. Those that aren't experienced will use the markings on the gear set itself to set depth. It can work but, the better way is to set depth by what the pattern looks like based on experience. This ensures the depth is set to the cut of the housing and not the gear set when lapped.
Differential noises generally: On decel, front pinion bearing; on accel, rear pinion bearing; certain speeds/light throttle, ring and pinion; on turns, the loaded side can be carrier or axle bearings.
Your option other than the dealer is to find a competent differential shop for a test drive and inspection, if deemed necessary.
Just to qualify my statement, once upon a time I did it for a living and have set up 3000'ish differentials.

Unfortunately after the dealer rebuilt the rear differential, I've literally got all the symptoms that you described. I've got gear noise upon acceleration and deceleration along with the harmonic resonances at the particular mph's that I listed. It's a real mess.

A level 3 technician at the dealership performed the rebuild.

Strange to me, the noises get louder as the oil warms up after driving 20 miles or so. I commute from York to Harrisburg on I-83. That drive us 26 miles. The noises are really loud by then.

The front differential sounds like it is dry in 4WD Auto. It makes a scraping, grinding or groaning noise that worsens in tight turns. It sounds like disc brakes that sat out in the weather and rusted, then the pads were applied. I need Chrysler to address that as well.

 

[Rob5589]

Sounds like a mess. Are they sure it isn't the transfer case? Seems odd that both diffs are troublesome at the same time. But anything is possible. Hope they get you squared away soon!

 

[The_Chemist]

Sounds like a mess. Are they sure it isn't the transfer case? Seems odd that both diffs are troublesome at the same time. But anything is possible. Hope they get you squared away soon!

The rear differential is definitely messed up. The original noise was made much worse after the rebuild, plus new noises are now existing after the rear diff rebuild.

As far as the noises when 4WD Auto is engaged, it could be the transfer case. I don't know at this point.

 

[Billet1500 4x4]

Thank you. I appreciate all the replies. This will help me a great deal when I return to the dealer, meet up with the Chrysler rep and try to hopefully and finally get this truck repaired correctly.

I'm going to try and make that happen this time (replace the entire assembly with one directly from the factory). Hopefully Chrysler will accommodate me!

That's a good point that you brought up about the housing being out of spec. I'm sure they all get assembled with the same shins, so that could have been the original high pitched noise.

Thanks!

Chrysler doesn't shim the carrier, They use a bearing tensioner that has to be torqued through the axle tube before the axle shafts are installed and then locked in place before sliding the axles in. They may not have checked for the proper turning preload on the pinion to verify they crushed the crush sleeve of the pinion properly.