Dodge Challenger Forum banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Ride of the Month Challenge!

1 - 20 of 29 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
Hi All,


2011 SRT here. I have rear diff whine.



A couple weeks back I had the dealership replace the rear diff gear oil. My invoice shows they added "75W140 Synthetic Gear Oil."


The whine is still there. Is it worth my time to try the same um.. viscosity 75W140 but use Royal Purple?


TY
 

·
Registered
Joined
·
2,111 Posts
I would take it back to the dealership and tell them what's going on. I have seen other threads here where some members were talking about adding more friction modifier to the rear end fluid..I am sure someone who knows more about that can chime in here. But usually weather your car is under warranty or not, when a dealership does repair work or anything to the car, that work is usually warranted for a year or more. Make them fix it...their the ones who changed out the fluid.
 

·
Registered
Joined
·
15,846 Posts
Oil brand or viscosity seldom cures a whine, once it starts whining not much you can do except swap in a new rear. If you have a groaning sound in the turns then new oil and additive can cure that, but not a whine.

Sent from my SM-N960U using Tapatalk
 

·
Registered
Joined
·
690 Posts
Mine makes noises after I had one of the half shafts pop off and dealer drained and refilled it, I'll probably add the additive in it this week see if it makes it quit down.

Sent from my SM-G955U using Tapatalk
 

·
Registered
Joined
·
629 Posts
A couple weeks back I had the dealership replace the rear diff gear oil. My invoice shows they added "75W140 Synthetic Gear Oil."


The whine is still there. Is it worth my time to try the same um.. viscosity 75W140 but use Royal Purple?
Some swear by Royal purple, so it's worth a try.

Is it worth your time? Absolutely. Not so sure it's worth taking the time to go to a dealer and have them change it, though.
 

·
Premium Member
2014 Challenger SRT 8
Joined
·
1,184 Posts
https://www.schaefferoil.com/170-gear-lube.html


Improves transmission shifting and gear efficiency.
Optimizes performance.
Enhanced protection against rust and corrosion.
Reduces operating temperatures.
Minimizes cold welding.
Exceptional extreme pressure properties to protect against wear.
Enhanced thermal and oxidative stability and durability.
Longer oil, seal and equipment life


It works...………….
 

·
Premium Member
Joined
·
4,353 Posts
The viscosity stuff cured my low speed groan, but the TSB that says to replace it with a new driveshaft didn't do anything for the whine. Mine sounds like there is a crotch rocket sitting just off my left bumper. It's really noticeable on a really smooth highway, at about 60. What do I do? Just turn up the tunes.
 

·
Registered
Joined
·
413 Posts

·
Registered
2015 RT 5.7 M6
Joined
·
9,270 Posts
My diff has been whining since I bought it CPO. I've tried royal purple and the whine is still there...even tried higher viscosity but did not help. Switched back to the recommended viscosity but RP brand. Seems like my whine is worse as the diff warms up. Also seems loudest when cruising around 40 mph. I tried to have the dealership replace it under warranty but no dice. Anyways, if you get the diff replaced some say that it may come back if you experience an instance of severe wheel hop.

Ah, disregard you have the getrag unit...mine is the ZF.
 

·
Super Moderator
Joined
·
14,919 Posts
Most Challengers seem to have the differential whine. It is not bad on my 2009 SRT but I can still hear it.

Does anyone know the actual cause of the whine? I wonder why Dodge didn't fix this after 10 years??

Typically, whine can be caused by lack of lubrication, worn or misaligned bearings or maladjusted or worn gears.
 

·
Registered
Joined
·
15,846 Posts
Most Challengers seem to have the differential whine.
Seems to be more pronounced on any car with an IRS since the rear is solidly mounted to the car and more easily able to transmit noise and harmonics throughout the car rather than a live axle in which the rear chunk hangs down apart from the car and the car is somewhat insulated.

I've been lucky so far, no whine at all and at 20K miles now.




Sent from my SM-N960U using Tapatalk
 
  • Like
Reactions: Fawls

·
Super Moderator
Joined
·
14,919 Posts
Seems to be more pronounced on any car with an IRS since the rear is solidly mounted to the car and more easily able to transmit noise and harmonics throughout the car rather than a live axle in which the rear chunk hangs down apart from the car and the car is somewhat insulated.

I've been lucky so far, no whine at all and at 20K miles now.Sent from my SM-N960U using Tapatalk
Could it be that Dodge feels that the whine is just normal for a car with an independent rear suspension and that's why they have taken no action?
 

·
Registered
Joined
·
413 Posts
Most Challengers seem to have the differential whine. It is not bad on my 2009 SRT but I can still hear it.

Does anyone know the actual cause of the whine? I wonder why Dodge didn't fix this after 10 years??

Typically, whine can be caused by lack of lubrication, worn or misaligned bearings or maladjusted or worn gears.

After reading all the posts.....I am wondering if the rear Diff Brace is partly the reason for the great results that I experienced. I noticed right away after installing the Brace I had a much stiffer ride. It is VERY obvious the Brace REALLY limits the Diff movement.

In stock form....I had TERRIBLE wheel hop at the Track. So much so the entire dash would shake and it made me worry if I was gonna lose a quarter panel or something actually important! After installing the B Woody Sway bar links (much heavier duty), and the 3 Spohn Adjusting Rods (much heavier duty) and the Diff Brace.....my ride quality went from being in a "luxury car" to being in a "race car".

I was surprised how flimsy the Factory parts really are. It is apparent all the flimsy parts "flex together". This gives you a soft ride under all conditions. The rear Diff must look like a "bobble head" going down the road. This MIGHT explain how there so many complaints on the Diff noise.

I gave up that silky smooth ride for a stiff one.......but now the car flat launches straight and true with zero wheel hop.

Regardless....my upgraded rear cradle "singed and howled" with the Factory fill. The RP is just what it needed. Happy 4th everyone
 

·
Premium Member
2014 Challenger SRT 8
Joined
·
1,184 Posts
Most Challengers seem to have the differential whine. It is not bad on my 2009 SRT but I can still hear it.

Does anyone know the actual cause of the whine? I wonder why Dodge didn't fix this after 10 years??

Typically, whine can be caused by lack of lubrication, worn or misaligned bearings or maladjusted or worn gears.
The gear ratio is where the noise comes from, the gears need to mesh properly.
Also, some whine more then others, read that’s normal.
 

·
Registered
2020 Dodge Challenger Hellraisin Scat Pack
Joined
·
3,658 Posts
Hi All,


2011 SRT here. I have rear diff whine.



A couple weeks back I had the dealership replace the rear diff gear oil. My invoice shows they added "75W140 Synthetic Gear Oil."


The whine is still there. Is it worth my time to try the same um.. viscosity 75W140 but use Royal Purple?


TY
Has a tech listened to the noise and offered his opinion? Have to mention that as engine output goes up, as vehicle weight goes up, the diff must be able to handle this and my experience has been over the years this means that small cars/engines have "quiet" diffs (and transmissions) while larger (and especially higher performance) cars have noisier diffs.

The difference between say my Boxster (2.7l 217hp engine, 5-speed manual) and my GTO (6.0l 400hp with 6-speed manual) diff/gear box noise was quite noticeable. But it was clear the GTO noise was a "healthy" noise.

The same was the case when I got a 996 Turbo with a 420hp 6-speed manual. The transmission/diff generated a lot of noise compared to the Boxster.

Currently I have a Mini JCW and a Hellcat. Have to say the JCW is a rather noisy car for a small car but it is due not so much to its 6-speed manual gear box/diff but those godawful run flat tires. Those things are ear killers.

With your car did the whine appear out of the blue or has it always been present?

Out of the blue is not a good sign. You can try a fluid change -- I'd stick with what the factory recommends -- but an out of the blue diff whine is probably not fluid related unless of course the diff has a fluid leak and the diff fluid level got low.

A whine that appears over time can be tire noise.

My Hellcat's diff whined at lower speeds and at "high" speed (>85mph) was quite noticeable. Was not a from new noise it just kind of appeared over time. Since the car is under warranty and because "noises" are hard to get the dealer to pay any attention -- "they all do that" -- I figured if there was a real diff problem I'd just drive the car until the problem got severe enough there would be no question about the diff.

But a couple of weeks ago the driver's side rear tire picked up a nail and I had to have both rear tires replaced. The new tires are the same as the ones that came on the car. The "old" tires were not worn that much and the rear tires and front tires were wearing evenly. (Had them rotated at 10K miles -- the flat tire happened at just under 14K miles -- and the tech noted the tread depth on the service invoice -- I had the oil service done at the same time -- and both front and rear tires had the same tread depth.)

To my mild surprise the "diff whine" is much less now than it was. It would appear the whine was mostly tire noise. To be sure I can still hear the diff -- no diff that can handle the Hellcat's engine output is going to be a quiet diff -- but the noise is no where as bad as it was.

Bottom line is you need a professional's opinion as to whether the noise is normal or abnormal and is it coming from the diff or some other place. (Some few years back my Turbo manifested a pretty loud howl at speed. Long story short the cause turned out to be some relatively minor front tire alignment issue. The tech who checked the car showed me how the front tires were manifesting feathering and signs of scrubbing due the alignment. But when the noise appeared -- over a drive of hundreds of miles -- I was convinced a bad wheel bearing or even the front diff (the car was AWD) was the cause.)
 

·
Registered
Joined
·
629 Posts
Has a tech listened to the noise and offered his opinion? Have to mention that as engine output goes up, as vehicle weight goes up, the diff must be able to handle this and my experience has been over the years this means that small cars/engines have "quiet" diffs (and transmissions) while larger (and especially higher performance) cars have noisier diffs.
Can't say that I ever heard that theory before. If true, the diff in my Peterbilt must be audible from a mile away.
I always thought that noise came from poorly set up gears, and/or poor quality gears.

Then again, even the best setup can be ruined by improper break-in.
 

·
Registered
Joined
·
413 Posts
Do you have an R/T? My 2009 SRT is definitely not a luxury ride. It is permanently set in "sport mode."
My 16 R/T Scat Challenger rode like a luxury car before the suspension upgrades. It was a Sports car with a Luxury car ride. Now...it rides like a Sports car. I LOVE it....but it is a big difference. Mine also is always in Sport mode ;)
 

·
Registered
2020 Dodge Challenger Hellraisin Scat Pack
Joined
·
3,658 Posts
Can't say that I ever heard that theory before. If true, the diff in my Peterbilt must be audible from a mile away.
I always thought that noise came from poorly set up gears, and/or poor quality gears.

Then again, even the best setup can be ruined by improper break-in.
Not a theory. My experience with a number of cars over the years. The difference in drivetrain noise between my Boxster and my VW Golf was noticeable. The VW had a 90hp 136 ft lbs of torque 1.9l diesel engine coupled to a 5-speed. Vehicle weight less then 2900lbs. The Boxster had a 217hp 192 ft lbs of torque 2.7l gasoline engine coupled to a 5-speed. Vehicle weight less than 2900lbs. The drivetrain noise from the VW was very subdued. Rather a quiet running car. Not Lexus quiet but pretty quiet.

The Boxster was noisier.

Then I sold the VW and bought a GTO with a 400hp 400 ft lbs of torque 6.0l V8 coupled to a 6-speed. Seem to recall the GTO weighed in around 3600lbs. Like the Boxster the rear axle was independently sprung. The GTO's drive train was noisier. It was at this time I also noticed how much slower the GTO's 6-speed shifted compared to the speed the Boxster's 5-speed shifted.

After I sold the GTO and ended up with a 996 Turbo with 420hp 413 ft. lbs of torque 3.6l twin turbo charged flat 6 coupled to a 6-speed (and AWD) (and a weight of around 3480lbs) its drivetrain noise was more than the Boxster's. And like the GTO the Turbo's 6-speed's shift speed was slow compared to the Boxster.

My Hellcat's got even those cars beat when it comes to drivetrain noise. The car is rather raw in this regard.

My mention here I got a chance to drive the Hellcat around 120 miles yesterday on mainly highways. The car is quieter than I remember it being. The difference is those 2 new rear tires. With the "old" tires the car manifested what I believe I described as a "scary" noise at "high" (~85mph) speed. But yesterday on the way home and on the same stretch of road as before even at higher speeds the "scary" noise was not present.

The implication is like with my Porsche cars the same with the Hellcat and that is I'll have to live with exceptional tire noise as the tires wear.

With both Porsche cars as the tires -- all 4 tires -- got close to needing replacement the tire noise became quite loud. It was always pleasant surprise, bonus, how much quieter the cars were after having new tires fitted. Really brought home how loud those high performance tires could get when they got worn down and got hard after too many heat cycles. I recall the front tires after 40K miles while there was some tread left, quite a bit actually, the rubber was hard and felt more like the plastic tires on a kid's Big Wheel than the rubber of a high performance tire

(I once tried to use the Boxster front tires beyond 40K miles and after a few more thousand miles I just had to replace them. The racket and their behavior became unacceptable/intolerable.)

In the case of say big rigs, the hardware is massive and doesn't spin as fast as automobile hardware. The housing has to be massive as well. The mass coupled tends to dampen the noise.

The times I've been close to a big rig going down the road with my windows down and this is rare mainly all I heard was tire noise. At slower speeds the engine/exhaust noise predominates.

The one time -- way back when I was a teenager -- I rode in a big rig after helping the driver load approx. 6000lbs of household items into the moving van -- I do not recall that much noise in the cabin -- in fact I recall being struck by how quiet it was in the cabin -- and I suspected the cabin was rather isolated from the rest of the truck to keep the noise in the cabin down to reduce the affects of noise on the driver. One thing to spend say 1K miles a month in a car another to spend 30K miles a month in a big rig.
 
1 - 20 of 29 Posts
Top