Hear over and over the 12 bolt can be noisy, my moser 12 is always quiet in a straight line, but i have no idea what differential is in it, pops like a sum bitc ever since i got it when i corner left and right, but in the straight lines, after hitting the track launching at 5-6000 over and over, i still have no humming from the rear, so why does so many have noise from them? My car has been 7.2 @ 97 in the 1/8th, so perhaps you power adder guys are the ones that manage to get them noisey? Got mine used BTW, so it has tons of abuse befor it landed in my ride.

 

My Strange 12-bolt's problem is that it came from the factory with poorly setup gears:





It whines at all speeds, acceleration and deceleration. POS is LOUD.

The HD Eaton posi that's in there is quiet in all but the tightest corners (like pulling into a parking spot). I aim to have a new set of gears put in this spring that will hopefully fix any issues.

As for why others claim so many problems with the 12-bolt, I have a feeling that has to do with marketing more than anything. That and the fact that 9 times out of 10 you'll only hear from the people that have problems (like me).

 

So, the Moser is better with the way they are setup stock possibly and the Strange is better with the way the TQ arm mounts perhaps? Sure there have been Moser users complain about noise, wyy didn't you fix the ring and pinion while you had tore down?

 

Why? Well...that's a loaded question.

1. The gears I wanted were backordered at the time (I think they were Superior gears)
2. The gears you see in that picture were already work hardened, so resetting those wouldn't have worked
3. I didn't have the time - I bought a house last year, and needed to be able to move the car to its new home. That meant no gears being reset until that happened.

That said, even the generality you made isn't entirely accurate - I helped a buddy install a Strange 12-bolt with 3.73s in his Formula a few years ago, and that thing was silent compared to this banshee. It just depends on the monkey turning the wrenches that day. The tag that was attached to my 12-bolt upon arrival was filled out by the tech that assembled it...he spelled my first name "Steev". That should have been my first indication that there would be a problem...I just didn't have the patience to fix it right then and there.

 

Ok, so you could have reset the pinion if you wanted, i have never tried, scared to without the dial indicators that i dont own yet.

Well, also people say after abuse, their 12 bolts have gone from quiet to noisy as well.

 

This is info that I put together last year on my website, as I and countless others have had problems with 12 bolts. Bob

The factory 10 bolt that came in these cars has a very small 7.5" gear. A variation of this rear was used back in the '70's in the Chevy Monza, then in the Chevy S-10. GM had to of known they would have warranty claims when they decided to use this rear in the 3rd and 4th gen f body's, apparently the cost of creating a stronger rear was higher than what they thought the warranty cost would be. This has been a real plus for the aftermarket, as a bone stock LS1 F Body with a manual transmission can break one of these 10 bolt rears! Many people have tried to beef these 10 bolt rears, spending a lot of money in the process. What they normally end up with is a rear that still breaks, as everything on these rears is too small.
The 12 bolt rears that are available for these cars is a step in the right direction. The 12 bolts are well known for being a stout rear that was a factory option back in the day in many performance cars. You can have a 12 bolt in an early Chevelle, Nova, Camaro, etc, and beat the snot out of it and not hurt anything. Put a 12 bolt into a late model f body that uses a torque arm, make a couple 4000 to 5000 rpm launches at the dragstrip, and I can just about guarantee you'll have a lot more gear noise on the way home. The torque arm seems to distort the housing on the 12 bolts, and it seems to happen to all the brands of 12 bolt rears. This does not happen to the 9 inch rears, and there is no price difference between the 12 bolt and nine inch rears. As the horsepower in our engines keep escalating, most people these days go straight to the nine inch rear. 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, better the 12 bolt does. The 9-inch also has a 0.125-inch larger ring-gear diameter and internal pinion support than the 12 bolt.

 

I already know about the 9 inc setups, i am still wondering why my Moser has not started making noise with the 4.30 gears launching 5500-6000 RPM? Luck?

 

Luck is most likely the answer. Bob

 

Ok, just had to know, so many complain about noise after abuse and mine is still just clunking in the turns.