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8-3/4" Ring & Pinion Noise - w/Pattern Pictures #2759547
04/03/20 04:29 PM
04/03/20 04:29 PM
Joined: Nov 2004
Posts: 25,050
Texas
GoodysGotaCuda Offline OP
5.7L Hemi, 6spd
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Looking to tap into the brain trust for some insight into my 489 case 8-3/4"

I have about 2,000 miles on this set of gears, which I purchased from Dr. Diff and set up myself. I have a noticeable gear whine at most any speed, more noticeable on decel. During my quarantine time I've decided to pull the 3rd member and see if there's anything that can do to address the issue while it is out.

Specs as follows:
New pinion and carrier bearings
Crush sleeve eliminator, set to "new" bearing turning torque w/beam in-lb torque wrench
New Motive 3.73s, measured 0.007" backlash [Spec 0.006"-0.010"]
Rebuilt SureGrip


Looking at my Yukon guide, my pattern seems to best match the top-left one shown under "acceptable patterns". At this point, I am not seeing anything that needs adjustment, but I know the gears are noisy.

yukon.jpggears1.jpggears2.jpg

1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - https://www.facebook.com/GoodysGotaHemi
2020 RAM 1500
[img]https://i.imgur.com/v9yezP9.jpg[/img]
Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: GoodysGotaCuda] #2759557
04/03/20 05:04 PM
04/03/20 05:04 PM
Joined: Dec 2004
Posts: 10,549
Rittman Ohio
fourgearsavoy Offline
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That pattern looks really nice have you inspected the bearings really close to see if there are any issues there. It's hard to suspect the gear set with a nice pattern like that twocents
Gus beer


64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60
Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: GoodysGotaCuda] #2759558
04/03/20 05:05 PM
04/03/20 05:05 PM
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Posts: 25,618
Rio Linda, CA
John_Kunkel Offline
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IMHO...after 2000 miles you're not gonna be able to "adjust" out the noise. Are you sure it's gear noise?


The INTERNET, the MISinformation superhighway
Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: GoodysGotaCuda] #2759560
04/03/20 05:13 PM
04/03/20 05:13 PM
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Posts: 29,648
Hamtramck, PA
Alaskan_TA Offline
Fluffy Balladeer
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Did you use the friction modifier in the sure-grip gear lube?

Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: Alaskan_TA] #2759564
04/03/20 05:27 PM
04/03/20 05:27 PM
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Posts: 32,882
Grand Prairie,Texas
stumpy Offline
I Win
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What ratio?

Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: stumpy] #2759573
04/03/20 05:54 PM
04/03/20 05:54 PM
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Posts: 29,648
Hamtramck, PA
Alaskan_TA Offline
Fluffy Balladeer
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Hamtramck, PA
Quote
3.73s,

Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: Alaskan_TA] #2759574
04/03/20 05:58 PM
04/03/20 05:58 PM
Joined: Jan 2003
Posts: 32,882
Grand Prairie,Texas
stumpy Offline
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OOPS! missed that. They might just be a little noisier naturally. I know my 3:91s were.

Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: John_Kunkel] #2759578
04/03/20 06:20 PM
04/03/20 06:20 PM
Joined: Nov 2004
Posts: 25,050
Texas
GoodysGotaCuda Offline OP
5.7L Hemi, 6spd
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Texas
Originally Posted by John_Kunkel
IMHO...after 2000 miles you're not gonna be able to "adjust" out the noise. Are you sure it's gear noise?


About as certain as I can be. I had 3.91s before that I ran for quite some time and as soon as the new gears went in this noise appeared.

I figured an extremely minor adjustment might be able to be made along with another 500mi gear break in. shruggy



My car is extremely quiet on the highway and the gears are certainly the noisiest contributor.


1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - https://www.facebook.com/GoodysGotaHemi
2020 RAM 1500
[img]https://i.imgur.com/v9yezP9.jpg[/img]
Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: GoodysGotaCuda] #2759599
04/03/20 07:07 PM
04/03/20 07:07 PM
Joined: Dec 2004
Posts: 10,549
Rittman Ohio
fourgearsavoy Offline
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Rittman Ohio
I would re-check your preload on the pinion bearings. I learned the hard way about deburring shims on a 12 bolt I rebuilt. The pinion bearing lost some of it's preload after a couple hard runs and gears started whining and I pulled back apart and reset the pinion preload and re-checked the pattern and it still looked good. Put it back in the Firebird and we lucked out it was quiet again. The only thing I could come up with was the stack of shims under the pinion bearing cup had edges on them that gave me a false reading. Just a thought shruggy
Gus beer


64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60
Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: fourgearsavoy] #2759609
04/03/20 07:45 PM
04/03/20 07:45 PM
Joined: Nov 2004
Posts: 25,050
Texas
GoodysGotaCuda Offline OP
5.7L Hemi, 6spd
GoodysGotaCuda  Offline OP
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Posts: 25,050
Texas
Originally Posted by fourgearsavoy
I would re-check your preload on the pinion bearings. I learned the hard way about deburring shims on a 12 bolt I rebuilt. The pinion bearing lost some of it's preload after a couple hard runs and gears started whining and I pulled back apart and reset the pinion preload and re-checked the pattern and it still looked good. Put it back in the Firebird and we lucked out it was quiet again. The only thing I could come up with was the stack of shims under the pinion bearing cup had edges on them that gave me a false reading. Just a thought shruggy
Gus beer


Thanks Gus, is this something I'm considering doing since I already have it on the stand. It won't be too much trouble to pull the carrier and check the pinion turning torque.


1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - https://www.facebook.com/GoodysGotaHemi
2020 RAM 1500
[img]https://i.imgur.com/v9yezP9.jpg[/img]
Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: GoodysGotaCuda] #2759610
04/03/20 07:45 PM
04/03/20 07:45 PM
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Benton, IL.
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DaveRS23 Online rolleyes
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I haven't been able to keep my 3.91s quiet for more than 1,500 miles or so for years. I just replaced a set of noisy 3.91s that had about 3,500 miles on them. I have put up with the whine for a couple of years, but it finally got to the point that I pulled them. U.S. Gears were in it before. The good Dr sent me a set of Motives this time.

We'll see how they do. I just got them in last week and have less than 100 miles on them so far.


Master, again and still
Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: DaveRS23] #2759617
04/03/20 08:02 PM
04/03/20 08:02 PM
Joined: Nov 2004
Posts: 25,050
Texas
GoodysGotaCuda Offline OP
5.7L Hemi, 6spd
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Texas
Originally Posted by DaveRS23
I haven't been able to keep my 3.91s quiet for more than 1,500 miles or so for years. I just replaced a set of noisy 3.91s that had about 3,500 miles on them. I have put up with the whine for a couple of years, but it finally got to the point that I pulled them. U.S. Gears were in it before. The good Dr sent me a set of Motives this time.

We'll see how they do. I just got them in last week and have less than 100 miles on them so far.


Ever try 85w-140 gear oil?


1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - https://www.facebook.com/GoodysGotaHemi
2020 RAM 1500
[img]https://i.imgur.com/v9yezP9.jpg[/img]
Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: DaveRS23] #2759621
04/03/20 08:06 PM
04/03/20 08:06 PM
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Fulton County, PA
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CMcAllister Offline
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Occasionally, you'll get a set of performance gears that will make some noise, regardless how pretty the pattern is. Some brands are worse for that than others. I've had good luck with Motives in the past.

"Whine" has different meanings for different people.Do you have to wind the windows up, turn the radio off and cock your head around to hear it or does it sound like a firetruck going down the road.

Typically, you have to get the set up off a considerable amount to make an otherwise quiet set of gears noisy. Those pictures do not look "off". I wouldn't touch that set up. I would check the turning torque of the assembly. I would maybe open up the backlash some and see what it looks like. But it may be a live with it or put new gears in it decision.

Motives are usually a good choice. Unusual for them to be excessively noisy. Housing (carrier) machining can also effect noise. I've seen housings so far off that they had to be replaced to keep the car out of the shop.


If the results don't match the theory, change the theory.
Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: GoodysGotaCuda] #2759629
04/03/20 08:23 PM
04/03/20 08:23 PM
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Benton, IL.
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DaveRS23 Online rolleyes
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Originally Posted by GoodysGotaCuda
Originally Posted by DaveRS23
I haven't been able to keep my 3.91s quiet for more than 1,500 miles or so for years. I just replaced a set of noisy 3.91s that had about 3,500 miles on them. I have put up with the whine for a couple of years, but it finally got to the point that I pulled them. U.S. Gears were in it before. The good Dr sent me a set of Motives this time.

We'll see how they do. I just got them in last week and have less than 100 miles on them so far.


Ever try 85w-140 gear oil?


It's all I run.


Master, again and still
Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: DaveRS23] #2760080
04/04/20 05:48 PM
04/04/20 05:48 PM
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ohio
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ruderunner Offline
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As others have posted, the gear pattern looks good. Is this noise load dependent? Louder on acceleration or coasting?


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Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: DaveRS23] #2760136
04/04/20 07:51 PM
04/04/20 07:51 PM
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Omaha Ne
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Years ago I ran all the way up to 5:13's on the street without any noticeable noise. But that was 40+ years ago shruggy beer

Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: GoodysGotaCuda] #2760143
04/04/20 08:09 PM
04/04/20 08:09 PM
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West Plains, MO
DrCharles Offline
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Originally Posted by GoodysGotaCuda
Originally Posted by DaveRS23
I haven't been able to keep my 3.91s quiet for more than 1,500 miles or so for years. I just replaced a set of noisy 3.91s that had about 3,500 miles on them. I have put up with the whine for a couple of years, but it finally got to the point that I pulled them. U.S. Gears were in it before. The good Dr sent me a set of Motives this time.

We'll see how they do. I just got them in last week and have less than 100 miles on them so far.


Ever try 85w-140 gear oil?


Interesting. I have a Dr. Diff-built chunk with 3.91's in it, probably Motive. If there's any whine at all, I can't hear it over the headers and 3" (to the bumper) exhaust. shruggy
But I only have 90 miles on it so far. And I put in 85W-140 with the pouch of additive that he included in the package.

Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: ruderunner] #2760161
04/04/20 08:55 PM
04/04/20 08:55 PM
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Posts: 25,050
Texas
GoodysGotaCuda Offline OP
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Originally Posted by ruderunner
As others have posted, the gear pattern looks good. Is this noise load dependent? Louder on acceleration or coasting?


It is load dependent, but up to a certain point. If I am on the highway where I just need to touch the throttle to maintain speed, the noise is nonexistent. Otherwise accel/decel is audible. I also hear it at lower speeds as well.


I do have full exhaust and pretty aggressive sound insulation, so the engine noise is pretty well mitigated. Louder mufflers, loud fuel pump, windows down, etc it wouldn't be problem, but I am trying to make the car the best it can be all-around.


I am going to put some 85w-140 in it and run it, accept it for what it is. I can't justify tearing into the gears to just double-check pinion bearing preload which I had already double-checked before. I'll just chalk it up to it being a hot rod part and there's going to be variance in the parts which I cannot control.

Last edited by GoodysGotaCuda; 04/04/20 08:57 PM.

1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - https://www.facebook.com/GoodysGotaHemi
2020 RAM 1500
[img]https://i.imgur.com/v9yezP9.jpg[/img]
Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: GoodysGotaCuda] #2760218
04/05/20 12:21 AM
04/05/20 12:21 AM
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Kirkland, Washington
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Originally Posted by GoodysGotaCuda
Originally Posted by ruderunner
As others have posted, the gear pattern looks good. Is this noise load dependent? Louder on acceleration or coasting?


It is load dependent, but up to a certain point. If I am on the highway where I just need to touch the throttle to maintain speed, the noise is nonexistent. Otherwise accel/decel is audible. I also hear it at lower speeds as well.


I do have full exhaust and pretty aggressive sound insulation, so the engine noise is pretty well mitigated. Louder mufflers, loud fuel pump, windows down, etc it wouldn't be problem, but I am trying to make the car the best it can be all-around.


I am going to put some 85w-140 in it and run it, accept it for what it is. I can't justify tearing into the gears to just double-check pinion bearing preload which I had already double-checked before. I'll just chalk it up to it being a hot rod part and there's going to be variance in the parts which I cannot control.


I would definately loosen the backlash to .009. Did you measure the backlash at 4 different points on the ring? Maybe you have some ring gear runout. Changing to 85/140 ain’t gonna do squat for noise...IMO

Last edited by Pacnorthcuda; 04/05/20 12:22 AM.
Re: 8-3/4" Ring & Pinion Noise - w/Pattern Pictures [Re: Pacnorthcuda] #2760828
04/06/20 05:07 PM
04/06/20 05:07 PM
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fredericksburg,va
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cudaman1969 Offline
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I’d look at the pinion bearings,

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