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Old 06-26-2003, 08:07 AM
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Troubleshooting Driveline Vibration

in my 69' Camaro I replaced my 10-bolt 3.08:1 rearend with a new Moder 12-bolt 3.73.1. I have a terrible vibration at 55 MPH+ in the drive line and I can feel a "whir, whir, whir" at lower speeds. I had a new driveshaft built and balanced and still experienced the same problem. I just had the pinion angle and the transmission output shaft angle checked. The transmission shaft is at 4* down. The rearend was 1* down. I shimmed the rearend to 4* up to cancel them out. The vibration is better but it is still there. So I had the rear end and drive shaft runouts checked and they are all within proper tolerances.

I think that the 3:08 ratio was spinning the drive shaft much slower so I never noticed a vibration at that lower driveshaft RPM. Now that I have the proper 3:73 ratio, the vibration problems that were probably always there at much higher speed are now at a lower RPM and noticable.

My question is, 4* seems like a lot of angle. Would it be recommended to try and shim the transmission up a degree or two (to 2* down) and shim the rearend down to match at 2* up? Do you think this would make any difference?

I am currently looking at replacing the transmission mount. I believe there may be some metal to metal contact. I should have an answer today.

If I still have a vibration I am thinking of having my Munci M21 rebuilt. It is pretty worn out and 2nd gear is whining like no other. I do not believe the tail bushing is worn out though.

Any more advice???

Primadude (Joe)
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