My car has a moser 9" with a 3.90 gear and a detroit trutrac installed all assembled by moser. The car runs great, but only under slight throttle I will get a whining noise from the rear end. I'm not sure how to describe the loudness of it, but it's definitly noticeable inside the cabin. With the radio at a moderate level you can't hear it. If I'm going say 40 mph and completely let off the gas and just let the car coast there is no noise whatsoever, if I just push the pedal far enough to keep the car at a constant speed or slightly accelerate I will hear the whine. If I push the gas down a little more the whining appears to stop or at least quiet down. ( I can't tell because of the exhaust noise )

A few friends have seen and heard and it a few said it's normal with a 9" and that gear, others said it shouldn't make any noise, some said don't worry about it, others said fix it. I checked the fluid level and it's fine and fairly clean. I'm looking for opinions on whether this is normal or not and if it's something I should worry about? If I have the cutout open ( basically just before the rear end ) I can't hear the whine, with it closed I can hear it. Opinions / advise?

 

I have heard that some gears make more noise than others. What brand of gears do you have?

 

Not sure on gear brand. The rear end was already in the car when I bought it. The reciept just says bolt in moser 9" rear end with 3.90 gear and detriot trutrac and it was $2599 I think.

 

the Moser 9"'s are known to whine a bit after you get on it a few times.

 

That's what I figured as well, just wanted to get other peoples opinions. I guess I just won't worry about it.

 

I could hear the whine in my 9" until I went to the true duals and spin tecs. It seemed better after I drove it a few miles though. Might be just the break in period on the gears but if it's not real bad I wouldn't worry. Unless you've got some real HP you're not gonna break the gear!!