dgiven

I have a 93 firebird with a brand new 12 bolt moser in it. Im getting alot of viration but it seems to be the worst at about 60 mph. I have a spohn adjustable torque arn and a urathane tranny mount. I have jacked up the car and run it on the stands and cant seem to issolate the problem, I even removed the driveshaft and ran it and the vibration is gone so I would guess that it has to be in the rearend. Im hope that you guys can give me some advice on what to do with it.
Thanks Dave

OBE1 95Z28

You probably need to adjust the pinion angle on your adjustable torque arm; negative 2 degrees is a good starting point.

dgiven

I guess that I forgot to mention that I have the pinion angle set at -2 degrees allready.
Thanks Guys

TUFF LT1

Here is a pretty good thread to give you some ideas.

http://web.camaross.com/forums/showt...ibration+moser

I had a vibration after installing my moser but it wasn't the rear, my wheels and tires were out of balance. Make sure that you lubbed up that polly tranny mount. Also if the vibration was gone after you removed your driveshaft than the vibration could have been caused by the driveshaft. If you still have it up on jacks, try taking the wheels off and leaving the driveshaft on (but rotate it 90). Good luck.

dgiven

I have had the wheels and tires balanced (the tires are new) I have had the driveshaft shortened 1/2" new universials and balanced. I have the wheels and brakes off the car and the vibration is still there. I did rotate the u joint 90 degrees and it is still there. I ran the car on the jack stands and the vibration showed up at about 50 mph and seemed to get worse as the speed increased. THe vibration seems to be coming from the center section of the rear end but I really cant be 100% sure. Im to the point (if I hadnt had the shaft shotened) to just put the old rearend back in the car to see if the vibration goes away.
There are probably alot of you can attest to just how very FRUSTATING it can be when you wait all winter to drive the car and you cant because of a stupid problem.
Thanks again guys

Nasty94Z28

Iam having the same Vibration and I am getting real made at the car but I havn't check anything yet.

dgiven

Ithink that I mentioned that I also have a spohn adjustable torque arm on the car aswell as the moser 12 bolt. I called moser today and they told me to remove the spohn torque arm and reinstall the factory one and that the vibration would go away.........garanteed. Well let us just say that it went from 50 mph to 70 mph and the faster I went the worse it got. I aslo called spohn and Steve told me that they also sell moser rearends and that everyone they sell they recommend that they take the rearend and have the rearend setup properly (back lash) etc. I will be calling moser back tomorrow and as far as Im concerne they had better do something to rectify the problem OR ELSE. BTW when I asked the guy at moser what would happen if the torque arm swap didnt solve the problem what my next option was......he had no answer for me........I wasnt born yesterday so I really didnt think that his suggestion would fix the problem.
As it stands right now....as far as Im concerned I would stay away from anything with the name MOSER on it..... in my opinion. I will update tomorrow after I talk to moser again
Thanks Guys

97FormulaWS-6

I had a similar problem with my stock 10-bolt when I swapped the gears... spent a lot of $$, and an entire season trying to find the demon... never did...

Ended up replacing the entire suspension and driveline from the tranny back; that fixed the problem, but cost me like $4K...

Not what you want to deal with, trust me.

Good luck on your challenge though...

I think I've heard of this with Moser 12-bolts though, There was a few of them like this either last year or the year before, don't remember what the resolution was though.

dgiven

I guess the other thing that I forgot to mention was that the car was as smooth as silk before the rearend was put in. Im thinking of putting the stock rear back in the car to see if that solves the problem....but I guess I will give moser a chance to solve the prolem.

97 RedSS

I'd take your Driveshaft to another shop and have them computer balance it to make sure thats not your problem..When they shortened it they should have rebalanced it so maybe they didnt do it correctly...I've never had any issues with my Moser by the way...oh yeah..they did send me the wrong axles at first(spool axles!)

Cody

Roadie

the problem is in the driveshaft or rear end... the cheapest place to start is the driveshaft. Have it re-balanced to make sure they didn't have it set up incorrectly when they first balanced it.

if the problem still occurs, you've isolated it to the rear end. It could be a bad yoke, ring gear out of balance, etc.

dgiven

I am very confident with the job that my guy did on the driveshaft, they have been in business for years and Ive never heard anything bad tobe said about them. Im nowalmost 100% sure it is something in the rearend. Im at this point really disappointed in the product....I hope that will change and soon.

526 SS 96

I had a vibration problem when I installed my moser 12 bolt. Check your torque arm clearance between it and the DS tunnel. If it is not atleast enough for you to fit your finger through this might be your problem. As the car speeds up there is more down force on it causing the clearance to be enven less. This was the problem I had, and I checked the DS for balance 3X, I even took the rear end compleetly appart and had the axles checked for run out, but in the end it was the torque arm rubbing against the tunnel (Real nasty vibration). It took a couple of days of driving to see the wear marks against the DS tunnel. I fixed it with a 2 LB hammer with about 3 rages tapped to it so I wouldn't scratch the tunnel up. The clearance problem is not likely to be on top, but rater towards the the side of the tunnel.

Boosted_Z28

As stated earlier, I would still have the driveshaft double checked for balance...it's the easiest and cheapest thing to do at this point. Please post when you have an update or resolved the problem.

dgiven

Well I have had the driveshaft done again. The first time it was done they left the harmonic balancer on the tranny end of it so I had them redo it and remove the balancer. I am now 100% sure that it is not the driveshaft. I have posted another thread in fbody tech regarding a possibilty of it being my fluid damper harmonic balancer????? so please read it and PLEASE comment, I am really tired of the problem.
Thanks guys
P.S. I will double check for the torque arm hitting the tunnel but Im pretty sure it isnt that.


Dave