New 3:55 gears always howl. True or False?

Posted By: NOrrTH

New 3:55 gears always howl. True or False? - 04/02/15 08:34 PM

I had a very respected Mopar guy who runs a tranny and rear end shop rebuild my 489 pig. He advised against the 3:55 gear because he said they don't cut the teeth the same way as they used to and they ALL howl now regardless of brand. It just affects the 3:55 gear set for some reason. He also said that if I was determined to go with the 3:55, the best thing to do was find NOS factory gears.

Anyway I went ahead and they do howl around freeway speeds. I thought I could live with it but the gear reminds me its there over and over again. So now I'm thinking of 3:73...

Anyone else heard of this?

Posted By: hemi71x

Re: New 3:55 gears always howl. True or False? - 04/02/15 08:50 PM

That's BS.
The gears aren't set up properly.
He's blowing smoke at you.
Need to find someone else that knows what they're doing, and talking about.
When i first started out as an auto mechanic, i worked at a shop doing differentials, here in my city.

Posted By: an8sec70cuda

Re: New 3:55 gears always howl. True or False? - 04/02/15 08:59 PM

Quote:

That's BS.
The gears aren't set up properly.
He's blowing smoke at you.
Need to find someone else that knows what they're doing, and talking about.
When i first started out as an auto mechanic, i worked at a shop doing differentials, here in my city.

Posted By: AndyF

Re: New 3:55 gears always howl. True or False? - 04/02/15 09:07 PM

That just doesn't make sense. Give DoctorDiff a call and see what he can do for you. He is in Montana which isn't a huge distance from B.C.

Posted By: NOrrTH

Re: New 3:55 gears always howl. True or False? - 04/02/15 09:43 PM

Thanks guys

Posted By: Darryls-Demon

Re: New 3:55 gears always howl. True or False? - 04/03/15 04:31 AM

I have a 3.55 gear set in my Challenger, every part is new and was bought from Doctor Diff and doe`s not howl at all.
I have 5000 miles on the setup.

Attached picture 8479312-IMG_1276.JPG

Posted By: RapidRobert

Re: New 3:55 gears always howl. True or False? - 04/03/15 04:59 AM

I submit that they were a set that was setup wrong & howled for a prior owner & he is (now) attempting to pawn them off on you to cut his loss(es). EDIT Competent and crooked are two different attributes & they ain't mutually exclusive. The tip off (to me) on this deal was him blaming the numerical ratio choice as being the problem

Posted By: SomeCarGuy

Re: New 3:55 gears always howl. True or False? - 04/03/15 05:03 AM

Good grief

Posted By: GoodysGotaCuda

Re: New 3:55 gears always howl. True or False? - 04/03/15 05:09 AM

Quote:

That's BS.
The gears aren't set up properly.
He's blowing smoke at you.
Need to find someone else that knows what they're doing, and talking about..

Posted By: Pacnorthcuda

Re: New 3:55 gears always howl. True or False? - 04/03/15 05:11 AM

The quietest 3.55 aftermarket is the U.S./Strange. I am currently running a set, and it's NOT noisy. In fact, it's quieter than 2 of the 3 factory 3.55's I've ran.

Posted By: GY3

Re: New 3:55 gears always howl. True or False? - 04/03/15 01:25 PM

I bought a brand new 3rd member from Mancini a few years back. I'm not sure who's 3.55 gears they used in assembling it but it's quiet as can be!

Posted By: rarefish

Re: New 3:55 gears always howl. True or False? - 04/03/15 02:38 PM

I bought a used third member with 3.55 gears years ago and when I installed them they howl. I put up with it for a long time. Then about 5 years ago I bought a new OEM 3.55 ring and pinion from Mancini's. I had a one man shop that does only rear ends, set them up with all new bearings. When I installed them they also howl like the last set just at a different rpm range. The guy told me that the gear pattern looked great when he set them up. I have had people tell me the howl might be coming from the axle bearings, but I don't believe that.

Posted By: TheTieWrapKid

Re: New 3:55 gears always howl. True or False? - 04/03/15 05:36 PM

FALSE !!

Posted By: moper

Re: New 3:55 gears always howl. True or False? - 04/03/15 05:47 PM

Any gear can be noisey if there's a problem. Problems are not always with the gears themselves, or even from the chuck. But - if there are not other issues, and they are broken in proerly, no gear ratio in and of itself will be noisey.

Posted By: MuuMuu101

Re: New 3:55 gears always howl. True or False? - 04/03/15 06:30 PM

Quote:

Any gear can be noisey if there's a problem. Problems are not always with the gears themselves, or even from the chuck. But - if there are not other issues, and they are broken in proerly, no gear ratio in and of itself will be noisey.

This is what I was thinking. My friend who built my 489 case 3.55 gears is very picky about how it's set up. Even when I was putting my 8 3/4 together he didn't want me to consult anyone but him. He was extra particular about how the gears were broke in, especially with a 489 case that has a crush sleeve. IIRC he states 20 minutes of light street driving and 2 hours of rest to cool down for about 3 cycles, always use an 85w gear oil or higher, and no burnouts/towing for the first 500 miles.

Posted By: Sxrxrnr

Re: New 3:55 gears always howl. True or False? - 04/03/15 10:36 PM

I have often heard that 3:90's are a problem. What is the collective wisdom on this allegation?

Posted By: mopars4ever

Re: New 3:55 gears always howl. True or False? - 04/03/15 10:41 PM

True or False I don`t know but I do know the 3.55 gears I had many moons ago did howl.

Posted By: NOrrTH

Re: New 3:55 gears always howl. True or False? - 04/03/15 11:50 PM

I broke in my "new" set very easy.

I don't want to mention any names, but this guy is very wealthy, has lived mopars since he was a kid, owns about 30 of them now, some of which are worth hundreds of thousands, drag races and is a bit of a Mopar celebrity in these parts...and he runs a transmission shop which has been doing rear ends for decades.

My point is, he's not some Craigslist back yard mechanic, hack.

Now I'm really scratching my head

Posted By: DaveRS23

Re: New 3:55 gears always howl. True or False? - 04/04/15 01:13 AM

There are particular gear sets than will be noisy, no matter the set-up. But that is more brand or batch specific, than ratio specific.

Posted By: TJP

Re: New 3:55 gears always howl. True or False? - 04/04/15 03:48 AM

Quote:

Quote:

That's BS.
The gears aren't set up properly.
He's blowing smoke at you.
Need to find someone else that knows what they're doing, and talking about.
When i first started out as an auto mechanic, i worked at a shop doing differentials, here in my city.

The other common Fallacy is that the lower you go the more they will whine, BULLS$heet I say. I have run gear sets as low as 5:13's in a street car that were quiet as a church mouse. I've run 3:91's, 4:10's, 4:30's, 4:56's, 4:88's and 5:13's. ALL QUIET noise wise WHEN SET UP PROPERLY. IF one is talking about special RACE only sets that could be a different story.

Posted By: Steve Bryant

Re: New 3:55 gears always howl. True or False? - 04/04/15 02:00 PM

False. My 8 3/4 3.55's sound exactly like my 3.23's sounded.

My E-Body car howls a little in 4th gear but that's my 4-Speed and not the rear end.

Posted By: Challenger 1

Re: New 3:55 gears always howl. True or False? - 04/04/15 03:11 PM

Quote:

Any gear can be noisey if there's a problem. Problems are not always with the gears themselves, or even from the chuck. But - if there are not other issues, and they are broken in proerly, no gear ratio in and of itself will be noisey.

The wrong pinon angle can cause a perfectly setup rear to howl.

Posted By: HotRodDave

Re: New 3:55 gears always howl. True or False? - 04/04/15 08:25 PM

Quote:

Quote:

Quote:

That's BS.
The gears aren't set up properly.
He's blowing smoke at you.
Need to find someone else that knows what they're doing, and talking about.
When i first started out as an auto mechanic, i worked at a shop doing differentials, here in my city.

The other common Fallacy is that the lower you go the more they will whine, BULLS$heet I say. I have run gear sets as low as 5:13's in a street car that were quiet as a church mouse. I've run 3:91's, 4:10's, 4:30's, 4:56's, 4:88's and 5:13's. ALL QUIET noise wise WHEN SET UP PROPERLY. IF one is talking about special RACE only sets that could be a different story.

And it is the same guys that can't get the gears to be quiet that can't get a 8.75 to last behind a slant 6. IT IS ALL IN THE SET UP!!!! Some guys break them time after time after time and say the rear is junk, then other guys set them up and they last for really long times. I am shocked at how many shops I have seen guy replace a pinion seal on a crush sleave rear and just tighten the nut with a big ole impact, there are not a lot of guys who reeeeeealy understand how to set up a hypoid gear.

Posted By: astjp2

Re: New 3:55 gears always howl. True or False? - 04/04/15 09:47 PM

Quote:

Quote:

Quote:

Quote:

That's BS.
The gears aren't set up properly.
He's blowing smoke at you.
Need to find someone else that knows what they're doing, and talking about.
When i first started out as an auto mechanic, i worked at a shop doing differentials, here in my city.

The other common Fallacy is that the lower you go the more they will whine, BULLS$heet I say. I have run gear sets as low as 5:13's in a street car that were quiet as a church mouse. I've run 3:91's, 4:10's, 4:30's, 4:56's, 4:88's and 5:13's. ALL QUIET noise wise WHEN SET UP PROPERLY. IF one is talking about special RACE only sets that could be a different story.

And it is the same guys that can't get the gears to be quiet that can't get a 8.75 to last behind a slant 6. IT IS ALL IN THE SET UP!!!! Some guys break them time after time after time and say the rear is junk, then other guys set them up and they last for really long times. I am shocked at how many shops I have seen guy replace a pinion seal on a crush sleave rear and just tighten the nut with a big ole impact, there are not a lot of guys who reeeeeealy understand how to set up a hypoid gear.

You mean torque wrenches are not optional?

Posted By: Kern Dog

Re: New 3:55 gears always howl. True or False? - 04/05/15 03:11 AM

I read in Mopar Action magazine that the Mopar engineers chose their ratios based on several factors. One was in relation to the amount of times the pinion gear intersected the same teeth on the ring gear. Please forgive my vague description here, but the theory was that the fewer times the same teeth touched each other, the longer lasting the gearset was by spreading out the wear and the load. This explains why the Mopars came with some ratios different than GM or Ford. Numbers like 2.71, 2.76, 2.93, 2.94, 3.91 were rarely seen outside of the Mopar brand. the 3.23 and 3.55 were more common ratios though. GM used them as well as some GM specific #s like 3.07, 3.08, 3.42 and 3.73.

Posted By: 383man

Re: New 3:55 gears always howl. True or False? - 04/05/15 03:51 AM

Quote:

There are particular gear sets than will be noisy, no matter the set-up. But that is more brand or batch specific, than ratio specific.

I agree with this. Most gears will not make much noise if set-up right. But I have seen some that make noise (not alot of noise but some) and they were done by good shops. Working for a Dodge dealer I can tell you I remember a truck that a customer complained the rear was noisey. It was a brand new truck with the new to Dodge "American Rear" and this was around 2005 to 2008 as I dont remember which year. I ended up replacing the ring and pinion and the pinion and carrier bearings as per the Mopar tech adviser and it was no different when I was done. And we had the proper tools for it since we were a Dodge dealer. It was not alot of noise as it was a small whine at about 55 mph. In fact most people would not even complain but this guy must have drove this speed alot. So in the long run Mopar had me replace the full drum to drum rear and recheck all the settings including pinion angle which made no difference as it still had some noise. I do believe the whine noise in the complete new unit did happen at a slightly lower speed. In the end the custumer was told that small whine is normal as it was and as I said most people like you all and me would have never even thought it was noisey enough to complain about. The guy took the truck happy with us as he saw me replacing the complete unit because the service manager brought him in the shop so he could see for himself we replaced the drum to drum unit. Ron

Posted By: Moe

Re: New 3:55 gears always howl. True or False? - 04/05/15 02:06 PM

My rear end builder says the Richmond gear sets like to howl. He uses US Gear only.

Posted By: 2boltmain

Re: New 3:55 gears always howl. True or False? - 04/05/15 03:19 PM

Quote:

I have a 3.55 gear set in my Challenger, every part is new and was bought from Doctor Diff and doe`s not howl at all.
I have 5000 miles on the setup.

Thats a nice challenger- or as young ones might say, Noice!!

Posted By: Twostick

Re: New 3:55 gears always howl. True or False? - 04/05/15 04:44 PM

Quote:

Quote:

There are particular gear sets than will be noisy, no matter the set-up. But that is more brand or batch specific, than ratio specific.

I agree with this. Most gears will not make much noise if set-up right. But I have seen some that make noise (not alot of noise but some) and they were done by good shops. Working for a Dodge dealer I can tell you I remember a truck that a customer complained the rear was noisey. It was a brand new truck with the new to Dodge "American Rear" and this was around 2005 to 2008 as I dont remember which year. I ended up replacing the ring and pinion and the pinion and carrier bearings as per the Mopar tech adviser and it was no different when I was done. And we had the proper tools for it since we were a Dodge dealer. It was not alot of noise as it was a small whine at about 55 mph. In fact most people would not even complain but this guy must have drove this speed alot. So in the long run Mopar had me replace the full drum to drum rear and recheck all the settings including pinion angle which made no difference as it still had some noise. I do believe the whine noise in the complete new unit did happen at a slightly lower speed. In the end the custumer was told that small whine is normal as it was and as I said most people like you all and me would have never even thought it was noisey enough to complain about. The guy took the truck happy with us as he saw me replacing the complete unit because the service manager brought him in the shop so he could see for himself we replaced the drum to drum unit. Ron

They had to do this with my 03 Ram with the 9.25 SG. They rebuilt the original one with all new stuff and it still was noisy. It sounds like it was similar noise wise to yours and had the dealer not jerked me around on some other issues I would likely never have put in a claim, but...

So they dialed the case and found it was out of spec and ordered a new housing and filled it up with new parts. When I asked why they didn't just install a drop in complete unit, I was told that a drum to drum 9.25 wasn't available and they had to build them at the dealer from scratch. Sounded like a fairy tale to me but either way I had a new diff under my truck.

Of course they still managed to get into my wallet for a few hundred because the parking brake shoes were FUBAR and not covered under warranty. $125 a set for the shoes

plus brake job labor now because that's a separate repair.

I hate dealerships...

But the diff in mine is now silent.

Kevin

Posted By: mikemee1331

Re: New 3:55 gears always howl. True or False? - 04/05/15 08:37 PM

ok, so that exactly makes them howl? I have a set of 4:10 Richmond that howl like crazy. when everyone says they are not set up right, what is not right??

Posted By: terzmo

Re: New 3:55 gears always howl. True or False? - 04/05/15 09:14 PM

same person...one set howled like a banshee...second set was quiet as a SBD...

Posted By: RapidRobert

Re: New 3:55 gears always howl. True or False? - 04/06/15 02:42 AM

Quote:

My rear end builder says the Richmond gear sets like to howl.

My rear end guy (decades of exp) said Richmond gears are "hard to setup" quote unquote

Posted By: GTX MATT

Re: New 3:55 gears always howl. True or False? - 04/06/15 05:18 AM

I set up the Richmond 4.56s in my 8 3/4. Good pattern, took it for a short ride, let it cool 3 times. It said break them in 500 miles, I thought yeah ok, I can't resist that long. Plus drag cars don't do it, right? (They also don't drive on the street)

Layed into it 3rd gear from 30 mph and it got sideways hard. Gotta do it again. And again. And then it got noisy. They hum on the highway now, guess I'll be a good boy next time

Posted By: skicker

Re: New 3:55 gears always howl. True or False? - 04/06/15 05:29 AM

Quote:

ok, so what exactly makes them howl? I have a set of 4:10 Richmond that howl like crazy. when everyone says they are not set up right, what is not right??

I would think the checking depth on the pinion would be the problem. As to whether it is too deep or too shallow you can't see by simply looking at it.
As to how to get it out I don't think I would change the checking depth once the gears have been ran.
You can check the backlash and adjust it yourself with a dial indicator. I set the backlash years ago on one and never had an issue (removed an open carrier and installed a clutch pac)
I got a bad feeling the 391's I just set up are going to howl. I don't have them in yet and it may not be an issue but it was hinky trying to set the backlash...almost .003 difference measured on the ring gear at 4 different locations.

Posted By: BigBlockMopar

Re: New 3:55 gears always howl. True or False? - 04/06/15 09:59 AM

Years ago I set up a set of 3.9 Richmond gears as a first try and they were quiet as can be.
Few years on, I reset the backlash on the gears and now they're noisy.