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Re: drive line vibration
[Re: dynamite]
#887245
12/24/10 01:52 PM
12/24/10 01:52 PM
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Joined: May 2003
Posts: 15,487
Florida
scratchnfotraction
I Live Here
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I Live Here
Joined: May 2003
Posts: 15,487
Florida
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do you have big and small u-joints on the one shaft?
both big and both small?
does your guy spin the shaft at speed it will see in the car with the 3.91?
spinning it on a lathe is one thing,but high speed balance and check the run out on it is another thing
needs to be high speed balance as it will be spiining faster than the 2.76 gear
did you check the tail shaft bushing?
is the yoke engauged ito the tail shaft the correct length?
a little short and it will wobble in the tail housing
whats the angle of it compaired to the pinion angle?
maybe try turning the shaft around and put the tranz yoke on the other end
try a conversion joint on the "good" shaft and see if it still does it
Last edited by scratchnfotraction; 12/24/10 01:54 PM.
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Re: drive line vibration
[Re: scratchnfotraction]
#887247
12/25/10 04:47 PM
12/25/10 04:47 PM
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Joined: Mar 2006
Posts: 9,894
MI, usa
dvw
master
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master
Joined: Mar 2006
Posts: 9,894
MI, usa
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Quote:
do you have big and small u-joints on the one shaft?
both big and both small?
does your guy spin the shaft at speed it will see in the car with the 3.91?
spinning it on a lathe is one thing,but high speed balance and check the run out on it is another thing
needs to be high speed balance as it will be spiining faster than the 2.76 gear
did you check the tail shaft bushing?
is the yoke engauged ito the tail shaft the correct length?
a little short and it will wobble in the tail housing
whats the angle of it compaired to the pinion angle?
maybe try turning the shaft around and put the tranz yoke on the other end
try a conversion joint on the "good" shaft and see if it still does it
One thing missed here is transmision output shaft RPM.
I have the same problem on my Challenger. Ok with a 2.76, vibrates with 3.55 or 4.30. Vibrates with the clutch depressed with vehicle moving. Installed the 3.55 and the 4.30 in another car,no vibration. Swapped axles and drive shafts. Both u-joint angles are 1.5 degrees. One positive,one negative. It has a new tail shaft housing and bushing do to a previous failure. I never saw a bent trans output shaft until this year on a friends car I repaired. I'm wondering if mine might be bent as well. Just something else to think about.
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Re: drive line vibration
[Re: dynamite]
#887248
12/25/10 05:01 PM
12/25/10 05:01 PM
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Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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Quote:
I have vibration at cruise. But the thing is it is only there with the 3.5 inch drive shaft with the larger u- joints..when I put the small stock drive shaft the vibration is gone, but it is smoothe with the small shaft in.. Ideas ??
Have him build another shaft. Yes it showed good on his balancer but something other than the balance per se is effecting a prob when it is installed. yoke/ujoints/phasing/yoke engagement or something else. EDIT read all the posts and I think Scratchn has it covered esp put the yoke on the small shaft w a combo ujoint & cross your fingers
Last edited by RapidRobert; 12/25/10 05:25 PM.
live every 24 hour block of time like it's your last day on earth
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jeff57