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Which gearsets are quieter nowadays, D60 or 8 3/4?

Posted By: DaveRS23

Which gearsets are quieter nowadays, D60 or 8 3/4? - 10/14/19 05:25 PM

I have had 8 3/4s under my street/strip cars forever. I have only busted one or two over the years so overall durability in not an issue. My problem is that they are always quiet at first, but man do they get noisy after a few years. The 3.91s I have in there now have gotten so loud that I can hardly hear the radio over them. I pulled them out last winter and checked everything and it all looked good. I can usually get 4 or 5 years (less than 10,000 miles) before they get unbearably noisy. That is the situation now.

Now I have a truck D60 that I can cut down, flange and set-up for the Cuda. It will obviously cost more to do that than replace the ring and pinion in the present 8 3/4. The only real reason I would go to the time and expense of changing over to the Dana is if it were to stay quiet.

I hit the track with Drag Radials 2 or 3 times a year if that matters. Auto trans, 1.5/1.6 60's, 3,900lbs.

So my question is: are the gear sets for the Danas any quieter than the gear sets for the 8 3/4s over time? Any help and direction here would be appreciated. I have to do something with the rear gears this winter. I just need to decide which is the better route to quiet rear gears over the years.
Posted By: MoonshineMattK

Re: Which gearsets are quieter nowadays, D60 or 8 3/4? - 10/14/19 09:15 PM

I think there must be something wrong if your axle is noisy. The 8 3/4 in my charger has well over 25,000 miles since the early 2000's and has been quiet the whole time.
Posted By: Cab_Burge

Re: Which gearsets are quieter nowadays, D60 or 8 3/4? - 10/14/19 10:38 PM

Your having luck I never had, none of the good 8 3/4 gear sets I had set up by a good shop never made noise, even after cracking the outer edge of the ring gear teeth on every tooth work shruggy I would pull them on the race cars after 100 runs to check them, I had one tooth corner break off at the track in the burn out box and ruin that day. None broken while driving them after that by replacing them before the corners broke off work
I bent the heck out of the last 8 3/4 housing I had cut down to put in my old pump gas Duster street car that was half fast, 10.0 at 134. MPH corked up on pump Oregon 91 octane swill motor only with the air cleaner on devil I replaced it with a cut down Dana 60 out of a pickup and the car pushed so much easier after that I wish I had put a good Dana 60 in it to start with up twocents
I had tried 4 different gear sets in that 8 3/4 before breaking the ladder bar tabs off of the housing at Woodburn drag strip in around 2008 or 2009, 3:73,3:91, 3:91,4:10 and the final set of 4.30. That stupid car ran almost the same ET and MPH no matter what gear set was in the rear end confused I cracked the corners on all of the ring gears also whiney That rear end had a set of Strange 35 spline axles and a strange Engr. 35 spline spool in the 8 3/4 since day one also work
The stock set of Dana 60 4.10 gears are still in that car going strong, same thing on the stock Dana 4.56 gear set in my current S/P car up I had the rear cover off last year after a bunch of runs and they looked great, no noise or ring gear cracks boogie
IHThs thumbs
Posted By: 451Mopar

Re: Which gearsets are quieter nowadays, D60 or 8 3/4? - 10/15/19 06:24 AM

When my 4,150# Charger was running the 11's the limited slip of the stock 3.91:1 geared 741 case 8-3/4" started making bad noises.
After looking at options and costs to upgrade the 8-3/4", I just put in a Strange S-60 with 4.10:1 spool in the car.
I was going to say if it is a 489 Case 8-3/4", replace the crush sleeve with the solid spacer adaptor and shim package.
Posted By: Grizzly

Re: Which gearsets are quieter nowadays, D60 or 8 3/4? - 10/15/19 02:17 PM

You are not alone.

Every 8.75 diff I've ever owned roared at highway speed. Probably pinion bearing, I just live with it because I drive them so little, but hate it just as much as you do.

I've been waiting for someone to upload a Youtube video of how to do a full re-build of the 8.75 so I can know how to do one, but still no one has done it.

The 9.25's in the Rams are only a bit better but, same thing: pinion bearing replacement is required reading for a Dodge Owner.

The Dana that was in my diesels I didn't own long enough to comment, but I sure don't hear the 2500/3500 Owners complaining about them, so you might be on the right track with going the Dana route.
Posted By: Cab_Burge

Re: Which gearsets are quieter nowadays, D60 or 8 3/4? - 10/15/19 04:09 PM

I believe all the Cummins powered pickup had Dana 70 in the 3/4 tons and Dana 80 in the one tons up through 2004 when ma Mopar switch vendors to the cheaper American Brand rear ends down
Posted By: MoonshineMattK

Re: Which gearsets are quieter nowadays, D60 or 8 3/4? - 10/15/19 09:20 PM

Factory service manual has pretty good step by step instructions. My biggest challenge was understanding how pinion depth and ring gear offset effected the gear pattern. 742 uses shims to set pinion bearing preload from the factory. When I do a 489 case I use a kit to eliminate the crush sleeve.
Posted By: GoodysGotaCuda

Re: Which gearsets are quieter nowadays, D60 or 8 3/4? - 10/16/19 01:53 AM

I have Motive [Richmond] gears in my 489 case and however I set them up is too noisy for my liking. They're quiet as long as I am accelerating or under load but begin to get quite loud on light load/decel.

I may have to go back into the diff this Winter and try to make some adjustments.
Posted By: ericxnelson

Re: Which gearsets are quieter nowadays, D60 or 8 3/4? - 10/16/19 06:38 AM

I appreciate all the honest responses here. My 3.91's in the dart were always noisy af, and have been on the fence over upgrading but this makes me lean towards just going all in on an s60.
Posted By: DaveRS23

Re: Which gearsets are quieter nowadays, D60 or 8 3/4? - 10/16/19 01:07 PM

Originally Posted by GoodysGotaCuda
I have Motive [Richmond] gears in my 489 case and however I set them up is too noisy for my liking. They're quiet as long as I am accelerating or under load but begin to get quite loud on light load/decel.

I may have to go back into the diff this Winter and try to make some adjustments.


Sounds similar to mine. Quiet under load and under full decel. But VERY noisy in between. Makes cruising a pain and makes me want to just race all the time. biggrin
Posted By: moparx

Re: Which gearsets are quieter nowadays, D60 or 8 3/4? - 10/16/19 04:30 PM

goody, once the gears are run in for a while, i don't think you will get rid of the noise by re-adjusting them.
i have been wrong many times.
beer
Posted By: astjp2

Re: Which gearsets are quieter nowadays, D60 or 8 3/4? - 10/16/19 11:00 PM

Real dana spicer gears set up properly are as quiet as a Lincoln or Cadillac...
Posted By: DaveRS23

Re: Which gearsets are quieter nowadays, D60 or 8 3/4? - 10/16/19 11:10 PM

Originally Posted by astjp2
Real dana spicer gears set up properly are as quiet as a Lincoln or Cadillac...


Okay. Now where do I get them?
Posted By: topside

Re: Which gearsets are quieter nowadays, D60 or 8 3/4? - 10/17/19 12:13 AM

Last gearset I had that whined on decel was a pinion depth issue. Loud enough that it was obvious there was a problem.
Pulled the diff out and it was WAY off, had pretty much eaten the R&P.
I've also had a 130,000-mile untouched-original Road Runner 8.75 that had a slight whine pretty much all its life on the freeway, steady speed, but most of the 20 or so 8.75s I've had were quiet.
My Danas have all been quiet, whether they were street cars or drag cars.
Gearsets came from different sources.
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