Ok, does anyone have a 9" or 12 bolt in an F-body where the noise is tolerable? My Moser 9" sounds like one of those old air raid sirens and the noise gets louder the more load it is under.

I sent the third member back to Moser once, and the guy I talked to then said they switched the U.S. gearset to a Richmond gearset, and they replaced the bearings. When I put it back in, after about 75 miles, the noise came back. I called back and talked with someone else, and he said that there was nothing in the notes about changing to a Richmond gearset.

The guy also told me that putting an aftermarket rear in an F-body was guaranteed to make noise, there was no way around it.

I know I should expect some noise, but I can barely hold a conversation and my ears are almost ringing when I get out of my car. You can even hear the noise if you are standing on the side of the street when I pass by.

I have had some people tell me that it is possible to get one that is quiet and others that say you can't.

Do I need to go to a 12 bolt? Is it possible to have one that is tolerable?

Any opinions appreciated, sorry this was so long.

Thanks,
Kevin

 

TTT

 

Check your pinion angle. You want to set it at -2. This will cause the symptoms you speak of.

 

I am still running the stock torque arm, so i can't adjust my pinion angle. That is the same type of thing that Moser tried to blame it on, thinking I had an adjustable torque arm and my angle was off.

Thanks for the reply,
Kevin

 

Phat t/a has a 9" in his ta only noise i've ever heard is the locker engaging and disengaging... may want to try to get a hold of him and ask i know he's had it apart several times so it might have made noise at one time

justin

 

Yep all I hear from mine is maybe a slight gear whine at high speeds and the sounds of braking parts from the locker around a corner thats tight.

Check the angle with your stock torque arm. The way the rearend is setup, it could be way off.

 

I will check the pinion angle tomorrow to see if it is ok. If it is, should I send it back to Moser AGAIN or just forget them and have someone locally install new gears for me. I really just hate to have to pay for new gears already.

Keep the replies coming guys,

Kevin

 

Are you sure its the gears and not the bearings going out? Gears usually produce a howel, were bearing will cause noise along with vibration

 

Well, the noise was not there when I first put it in. It started after about 75 miles, which kind of makes me think it is the gears after the teeth get some wear to them. I just checked the pinion angle and by putting the angle finder under the pinion, it read about 4 degrees. The front of the pinion is angled up.

I don't know which way is - or + on the angle finder though.

Does this mean I need to get an adustable torque arm? Do you think I would be able to fix it with adjustable lower control arms?

Kevin

 

the propar way to find the angle is to place the finder on the driveshaft, get a reading. Then put the finder on the t-arm where it mounts to the rearend. subtract the two and you have your pinion angle

 

it read about 4 degrees. The front of the pinion is angled up.

That's not good -- too far off and to make it <much> worse, the pinion should be pointing down, not up. When the rear is under load, it will naturally want to force the pinion nose up toward the body of the car. That's why the typical pinion angle is about -2 degrees or so; IOW, pointing down toward the ground at 2 degrees from perfectly level.

Your rear is starting at +4 degrees and probably going to 5 or even 6 degrees positive. It sounds like Moser paid for a rebuild when it wasn't their fault.

 

Thanks for the advice, I will try to get someone to let me put it on their lift to check it properly tomorrow.

Kevin

 

The Moser 12-bolt I have was very quiet as recieved. Unfortunately, the original posi was defective and had to be replaced. A friend who is a very skilled mechanic, but not a "specialist" in rear-ends put it back together. It now has a moderate whine at very light load or when decelerating with the car in gear. I suspect that if setup meticulously it would be quiet, but it's not bad enough to mess with, given how I use the car. If it were a daily driver it would bother me enough to fix.

I don't see why a properly set up 9" would be any different.

Rich Krause

 

I checked the pinion angle today, the best I could by sliding under the car, and found the driveshaft to be at about 1-2 degrees and the torque arm was at 2 degrees.

 

Who did the orignal assembly of the differential? That may tell you why you (many of you) are having problems with so much gear noise.