I have posted many times about how insainly noisy my moser 12 bolt is. We have swapped gears 4 times, and I've broke posi units 3 times. I recently took it to DTS and had them put a spool and new 4:11 gears in it. It was dead quiet through break in. What a relief!!! But after break in the noise picked up and after a few launches.... once again insain gear noise. Here is the wear pattern. I have 600 miles on since the spool. Your thoughts?

 

Its off for sure. How is your pinion preload? Check that first, make sure its right then get another pattern.

 

Thanks Mr. Mzoomora.

I'm not a gear guy at all. But it sounds like I need to get someone to reset them up. Like I said they were quiet as could be through breakin. Could they of moved around that much??

 

Actually I just recieved a response from DTS and they said the following???? Your thoughts?

IT IS VERY HARD TO TELL BY PHOTOS IF THERE IS A SET-UP ISSUE, HOWEVER THESE F-BODY CARS ARE ALWAYS NOISY. WE RECALL YOU SAYING THAT YOU HAVE HAD DIFFERENT GEARS IN THE REAR AND THEY HAVE ALL BEEN LOUD?

F-BODY CARS ARE VERY DIFFICULT TO MAKE QUIET W/ ANY AFTERMARKET GEAR.
IF YOU WANT TO BRING IT BY TO HAVE US LOOK AT IT, THAT WOULD BE FINE, JUST LET US KNOW WHEN YOU ARE COMING.

THANK YOU

DTS CUSTOM SERVICES
1-877-874-7327 TOLL FREE

 

I'd take it to them and let them fix it. He is right about f-body's being noisey with aftermarket gears.

 

Those are definately off. coast side is okay, but drive face is way off.

 

Isn't technology great. Here is a video I took at the Track Friday from inside the car. Turn up your speakers and listen to the trip back down the return lane. Remember this is a daily driven street car. The noise is a little annoying!!!!!

http://masra.org/video/tagroupy/dan-3.wmv

 

That cam sounds huge, why? Isn't the c2 like a 224? What were you launching at 5,000?

 

My gears sound similar to yours in my 10 bolt

 

777 That was the open header drag car behind me that you hear while I'm waiting in line. Yes I have the MTI C2 cam which is 224/224 and there stage 2 heads. Car runs 11.60's I launch at 5,500-6K.

PS my heads, Cam, pushrods, etc will be for sale this winter if anyone is interested. Car dyno'd 420 rwhp na (the video is na) and 555 on a 100 shot.

Here is a pic of the launch from the outside.

 

nice launch!

 

After many emails back and forth to DTS, they basically say the wear pattern is fine and the gear noise they hear in the video is normal.

I'm no expert (but getting close..haha) on setting up gears/wear patterns. But several people has told me from the pattern it needs adjusted. But DTS says its fine. Anyone else have an oppinion?

I would just run it up to DTS but its a 4 hour round trip. I was just looking for a yes it needs an adjustment, or no put fluid in and live with the noise.

 

Sounds to me like theyre just trying to get out of doing the work.

The contact pattern on my gears (albeit a 10-bolt) was perfectly centered on both the coast and drive side of the teeth. My gears run dead silent in terms of whine, which is a nice feat considering how likely 4.10s are to whine. I would say that while youre not in any danger running a pattern like that, it could definately be improved upon.

 

Reading the following may help some but performance gears will be louder because of a harder (more nickle) steel and less contact patch.

When looking at a new set of gears you can barely see the contact patch where the gears were ran in at the factory before the final finish coating was applied. Set gear pattern up the same.

According to the pictures you are close. But if you look more closely you can see the pattern I am talking about (area without white marking compound).

 

Drive and coast look deep. Drive is way too toe and coast has a hard line at the bottom of the tooth.

First.... it looks like the outer pinion bearing race wasnt fully seated and after a few good launches, that was addressed and now the pinion depth is way too deep. I take it your pinion pre-load is pretty much nill at this point ?? Its either that, or the cat that did the set up initially, was stoned.

I have to address something I read..... something about F-bodies having noisy gears sets if you use an after market product ?? Wow. Thats news to me. I have been doing differentials for about 15+ years and have done hundreds of 7.5 and 7.75 10 bolt corp GM differentials (not to mention that the 12 bolt is really my favorite and kinda my specialty.) The only gear sets that made relative noise were (of course) Richmond, some of the 'Indian' Motive sets and what we refered as the 'romulan' Motive sets. To address this, would most likely give good reason that I have always insisted on doing my builds with US/Strange gear sets.

....and another thing. The only performance gear set that is helically cut any differernt for performance are the "high impact" gear sets from Richmond, some of the non-main stream Percision performance line and the high impact Mark Williams gear sets.

 

Are you saying that OEM gears are cut exactly the same as most aftermarket gears. I know a factory installed OEM ring and pinion is much quieter than all aftermarket installs I have heard.

 

I installed a set of MOTIVE 4.10 using their prescribed pinion setting depth and they whined bad.

 

Actually..... yes. In fact, USGear is and has been the choice manufacturer for OEM since the early to mid 60's. They made all 12bolt car and even the 7.5" and 7.625" 10 bolt gears used in the 93 and on F-body. If you purchased a OE set, a set from USGear or a set from Percision gear (see further explaination why below).... they would all be the same.

But when it comes down to helical, hypoid gear 'cutting'...... the thrust/pressure, impact and incident angles have a very small window they can be cut at for strength and noise considerations (8620 alloy). One of the biggest factors in a gear set noise, is the hardness or "Rockwell" number the gear set is hardened to at the time of manufacturing. This has been Richmonds biggest problem for years...... they basically 'Rockwell' out too hard and the materials resonate frequency, at that specific hardness, make they sing like no other.

Now, concerning the high impact (9310 alloy) sets used in professional racing like Top Fuel, Pro Stock and some Off road classes...... these gear sets are very soft so that the tooth can flex and not shear from the impact loading. They however, wont live in a street environment too long as the gear set will deteriorate from being too soft.

As for some more FYI, Percision gear bought USGear's tooling when they started their business when USGear themselves re-tooled to meet OEM demands..... as they also supply gear-sets to some Chrysler/Dodge housings (specifically the 9.25 and 9.375), Fords as well (specifically the 8.8 and the 10.25) and GM (specifically the 7.5 and 7.625, and some 8.5 and 9.5).

It really comes down to the installation. Sometimes you can not avoid noise because of some applicable irregularities and/or variances in the housing, possible run out and product tolerances. A 'supplied' depth number can either be crutial or it can turn out to be a good place to start. Not all differentials will set up at the recommend depth, due to the above variances. Most of the time, a tech with enough time in the business knows all of this and can set the pattern to minimize the noise or to increase tooth integrity. BUT...... there is some give and take here. If set up for, what you would call a performance set up like drag racing, the drive pattern would actually be set a little toe with coast centered, to combat gear tooth deflection from impact loading. But you run the risk of an increase in noise. A text book gear set up, is commonly set with coast and drive centered and is quiet.

In summation, there are way too many variables in differential set up that can be associated to noise or a differential being perfectly quiet. That is why you pay to have it set up correctly. Someone that has been in the business knows the in's and out's of just that. But, when you step into the "Performance" end of the business the variables increase. Because I can tell you by pulling off the cover weather you followed the break in procedure or not...... and that would be the basis if I were to warranty a gear set from noise. If its not followed to the "T"..... the gear sets WILL MAKE NOISE soon after you think they were broken in correctly. 99% of the time the customer is to blame for the noise from just that...... not following simple directions because they are impatient and they wanna go out and beat on the car to see what their money spent, just gained them in performance.

And thats the rest of the story..............

The first picture is what an idal pattern should look like. The second is a "performance" set up and the third picture is what would depict too little lash and/or too much pinion depth....which looks more like the supplied picture from TAGOES11S but his actual is more extreme:

 

Sounds like BS to me. After listening to that video I can say that you defienately have a problem. That rear is much louder than it needs to be.

 

Moser statement concerning gear noise found by reading at their web site www.moserengineering.com Products, Housings 12 bolt

There is a trade off. If you do race and have excessive horsepower you will need an aftermarket gear. But keep in mind the gears are made for strength and the ability to withstand the demands of racing. If you are using your automobile as both your daily driver and your race car, can you live with the more noise on a day to day basis? You need to decide this prior to purchasing an aftermarket gear.

Our gears are made from stronger 8620 steel made for 'shorter' gear patterns favoring the 'toe' of the gear, which under a load the gear pattern will move toward the heel for strength.