So I tore the 12bolt down AGAIN
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From: The Confederacy
So I tore the 12bolt down AGAIN I've had absolute hell with my moser 12 bolt. When I first got it, it was set up wrong and made noise. I had it reset up and it made it a little more quiet, but a few trips to the track ruined that. So then I had it completely rebuilt with a new R&P, bearings, and a solid pinion bushing. I used the solid bushing because the crush collar had lost it's tension on the last rebuild after a few hard launches. Now, the solid bushing rebuild was SUPER quiet, as quiet as stock and I have the 4.33's in it. Drove it for about 1,500 miles and took it to the track last Wed. Second launch I cut a 1.55 60ft time and it starts making noise on the return road when I am coasting down. I run the car 3 more times and drive it about 60 miles home. The rear was REALLY loud on decel around 45-55mph and wasn't too bad while cruising above 55 and accelerating. I drove it the next day to Birmingham and back (140 miles) and parked it. Well, last night I pulled the inspection plate to check the backlash on it. It was .0085, I was under the impression that anything between .008 and .009 was good?? I went ahead and pulled the carrier out and checked the carrier bearings along with the ring gear. The wear pattern is great, along with the bearings. I haven't pulled the pinion yet, but the teeth on it look fine and it rotates freely without any play.
Do I need to reinstall the carrier and take the backlash down to .006 or .007? Does anyone think that the backlash is causing all my decel noise?
Do I need to reinstall the carrier and take the backlash down to .006 or .007? Does anyone think that the backlash is causing all my decel noise?
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From: The Confederacy
Originally Posted by Kurtomac
off topic but what did you run?
check your pinion depth. You may need to drop it down a little and reshim the carrier. Is the wear pattern in the middle of the gear, base or tip of the gear. I bet the pattern is a little close to the carrier and needs to be more in the mid of the gear tooth. I think the typical shim for the pinion is around 0.023 in you mite try a 0.019. My $0.02
And yes 8-9 thous. is good. Another thing is your axles bolt in or c-clip? What carrier? and may also check pin in the carrier and make sure the bolt is tight and hasnt starting rubbing on anything. This is about all I can think of right now.
And yes 8-9 thous. is good. Another thing is your axles bolt in or c-clip? What carrier? and may also check pin in the carrier and make sure the bolt is tight and hasnt starting rubbing on anything. This is about all I can think of right now.
The backlash is in spec at .008". Anywhere from .006-.010 is ok. Check the pinion bearing preload -again- and see where it's at. My $$ is on the pinion being loose. Otherwise, check the left (driver side) carrier bearing to see if it's loose on the carrier. I pulled mine off by hand and knew that wasn't good. 
If both of those look good, I'd say remove the gear set and replace it with a Ford 9" gear set. Oh, and you'll need a new housing and other parts too.
If both of those look good, I'd say remove the gear set and replace it with a Ford 9" gear set. Oh, and you'll need a new housing and other parts too.
