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
OP
5.7L Hemi, 6spd
|
OP
5.7L Hemi, 6spd
Joined: Nov 2004
Posts: 25,050
Texas
|
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.
|
|
|
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
|
Joined: Jan 2003
Posts: 25,879 Rio Linda, CA
John_Kunkel
Too Many Posts
|
Too Many Posts
Joined: Jan 2003
Posts: 25,879
Rio Linda, CA
|
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: John_Kunkel]
#2759578
04/03/20 06:20 PM
04/03/20 06:20 PM
|
Joined: Nov 2004
Posts: 25,050 Texas
GoodysGotaCuda
OP
5.7L Hemi, 6spd
|
OP
5.7L Hemi, 6spd
Joined: Nov 2004
Posts: 25,050
Texas
|
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. My car is extremely quiet on the highway and the gears are certainly the noisiest contributor.
|
|
|
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
|
Joined: Jan 2003
Posts: 12,160 Benton, IL.
DaveRS23
Special needs idiot
|
Special needs idiot
Joined: Jan 2003
Posts: 12,160
Benton, IL.
|
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
OP
5.7L Hemi, 6spd
|
OP
5.7L Hemi, 6spd
Joined: Nov 2004
Posts: 25,050
Texas
|
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?
|
|
|
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
|
Joined: Dec 2005
Posts: 11,611 Fulton County, PA
CMcAllister
Mr. Helpful
|
Mr. Helpful
Joined: Dec 2005
Posts: 11,611
Fulton County, PA
|
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
|
Joined: Jan 2003
Posts: 12,160 Benton, IL.
DaveRS23
Special needs idiot
|
Special needs idiot
Joined: Jan 2003
Posts: 12,160
Benton, IL.
|
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
|
Joined: Dec 2014
Posts: 5,886 ohio
ruderunner
master
|
master
Joined: Dec 2014
Posts: 5,886
ohio
|
As others have posted, the gear pattern looks good. Is this noise load dependent? Louder on acceleration or coasting?
Angry white pureblood male
|
|
|
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
|
Joined: Apr 2006
Posts: 4,220 West Plains, MO
DrCharles
master
|
master
Joined: Apr 2006
Posts: 4,220
West Plains, MO
|
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. 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
|
Joined: Nov 2004
Posts: 25,050 Texas
GoodysGotaCuda
OP
5.7L Hemi, 6spd
|
OP
5.7L Hemi, 6spd
Joined: Nov 2004
Posts: 25,050
Texas
|
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.
|
|
|
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
|
Joined: Nov 2007
Posts: 21,831 Kirkland, Washington
Pacnorthcuda
Too Many Posts
|
Too Many Posts
Joined: Nov 2007
Posts: 21,831
Kirkland, Washington
|
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.
|
|
|
|
|