I got 3.73 moser gears thay have whined from the day thay where installed.
it is so loud I what to take them out! the pattern and the backlash look good.
do mosers gears just whine? can I do something to fix this?

 

Whine as loud as you are stating is most likely bad install of some kind. Might be pre-lods or gear pattern.

Post some pictures of the pattern.

 

Yeah my Moser gears whine. Well, more like scream.

 

Yup they sure do whine. Especially within a Ford 9". I switched to 85w140 gear oil and it quieted it down a little.

 

Just got mine installed about a week ago and have close to 300 miles on it....It operates very smooth and doesn't make any noise while coasting or slowing down, but between 45-65mph while on the gas it howls a bit (while crusing). Will be doing a fluid change around 500 miles and might try a different weight.

 

does Royal purtle help

 

It's funny cause all I ever hear from people is "Gears won't whine if you install em right."...

 

Mine seem to make a little noise but mine are richmond.

 

Here is a funny story about my gears.
I have Motive Performance 3.89's in my 9" rear. I posted numerous pictures of patterns showing various pinion shim packs ranging from .018" - .024" thick. The best looking pattern was .022" an many said to run it. Well it had an annoying level of whine.

I then readjusted the pinion shim packs trying almost everything and then verifying by driving how much whine was present. I tried .024" shim pack and no change in whine. I tried .020 and no change. I tried .018" and the whine reduced a great bit. I tried .016" and it screamed like hell. I settled on .019" and it has only a very slight bit but is very acceptable. This is where I currently have the pinion set.

The funny thing is the .019" pattern looks like *** but it is definitely the quietest setup. Thank god I have the 9" with removable gear case so pinion shim changes can be completely done in less than 30 minutes each time.

Some one explain that.

 

I have read that a ton of times. However, never from anyone who is really credible however. My rear end was assembled and installed by Cartek and I would hope they know WTF they are doing. My contact pattern looks good and I have moderate whine with 85w140 non-synth oil.

Something I notice, you ever sit at the end of a 1/4 mile when the Pro Mod/Gas cars shut down at the end? They whine like a crazy on deceleration.

I am not worried. I just drive it like it is my sister's friend.

\

 

4.30s here in my 9" and I only hear a VERY faint whine on decel, on at certain speeds. I would rather have a great contact pattern and deal with whine than have it quiet with a poor contact.

 

The whine happens to most diffs with 3.73-4.10 gears because of the pitch of the gears. But, the f-body transfers the noise from the panard bar to the quarters and ecos throughout the car, worse in a convertible. I've set up gears for years, and if you had soft rubber at the suspension points there would be almost no noise. If you run eurethane or aluminum bushings,etc... this noise would be worse. I have a Dana 60 from a big named customer and he worned me of this before I bought the rear end. I've noticed it with 12 bolts, 9", Danas, and tried different manufacturers ring and pinions. It ends up being the noise transfer through the body panels. Your diff is good. Hope this helps.

 

Thanks for the response. Everything you said certainly adds up.
I have aftermarket suspension with poly bushings, a convertible, 3.90's and did I mention f-body.

 

Pulled out 3rd member and there were small chips in the ring gear.....sent it back to moser

 

FACTORY installed mosers always whine. Ive had new gears (diff ratio) installed and it helped alot, but then again, after some hard launches you hear it again.

 

This is a common problem with the 12 bolts that use a torque arm. The nine inch rears don't seem to be affected by hard launches. Bob

 

Not an expert by any means, but over the years I have heard various reasons that basically point to a 12 bolt or 9" giving you some whine no matter how well set-up. Don't know which is more accurate.

1. Steeper gears. (ie ratios)

2. Harder gears (higher nickel content, etc.).

3. The fact that the gears are physically larger.

4. More solid suspensions with less give or damping, as a performance rear is usually installed in a performance car that probably has suspension mods.

Take your pick. Both my Moser (4.11's) and my Strange (3.73's) have definite whine but have performed just fine over considerable time.

 

Exotic Performance Plus strongly recommends the Moser nine inch. This rear is even tougher than the Moser 12 bolt, and the horsepower of the late model F Body cars keeps escalating every year, which requires a very strong rear. With the recent introduction of the 6.2L GM aluminum block and the excellent flowing 6.2 litre heads, the horsepower of these cars is going to just keep climbing at a very fast pace.The nine inch will handle the power, plus we prefer the way the torque arm is bolted to the nine inch in the same way the oem rear-end is attached. (This is the only good thing about the stock 10 bolt...) The Moser 12 bolt uses four short bolts to attach the torque arm, and they have a habit of loosening up, even when loc-tite is used. Why the nine inch is stronger than the 12 bolt. The 9-inch has an internal rear-pinion support that also supports the gear end of the pinion to limit gear deflection under high torque loads. This seems to be the major reason why the 9 inch doesn't start whining after high rpm clutch dumps, when the 12 bolt will pick up noise.The 9-inch locates its pinion gear lower on the ring gear to improve tooth contact, than the 12 bolt does.The 9-inch has a 0.125-inch larger ring-gear diameter and internal pinion support than the 12 bolt does. This is not much of a difference, but it is worth noting.
Put a 12 bolt into a early Chevelle, Nova, Camaro, etc and you can beat the crap out of it, and not hurt anything. Put one into one of our cars with a torque arm, make a couple 4000 to 5000 dragstrip launches, and I can just about guarantee you'll pick up gear noise. If it is a drag only car, you'll never know or care about the gear noise. Drive your car home from the track, and the noise will drive you nuts. I feel the torque arm stresses the 12 bolt housing, causing distortion. We have never seen this happen with the 9 inch housing. Bob

 

I check mine periodically and found them finger tight once. I have tried to remember to check them even more often after that unpleasant discovery.

Bob, even my track car still has a stereo. I turn up the volume when the gear whine gets on my nerves.

 

Sounds like to me you guys need to spot weld those four bolts and curses to Moser for such a shitty design. Why not the pair of long straight throgh bolts you can torque the crap out of.