drive line geometry shim specs
#1419330
04/13/13 11:19 PM
04/13/13 11:19 PM
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Joined: Nov 2007
Posts: 245
Western PA
OldMoparMan
OP
enthusiast
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OP
enthusiast
Joined: Nov 2007
Posts: 245
Western PA
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I have been working on my vibration problem which I believe is coming from the drive line angles being off on acceleration it's bad and on braking it's worse around 30 to 40 mph. I have found that the tranny is 2* down, the driveshaft is 3.5* down and the rear end is 0* so I believe I need a set of 2* shims to get the rear end up to the exact opposite of the tranny. Am I correct in thinking if I make a 5" long shim with a 2* angle it would correct the rearend angle or does anyone have a set they can measure for me. 
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Re: drive line geometry shim specs
[Re: OldMoparMan]
#1419332
04/14/13 12:51 AM
04/14/13 12:51 AM
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Joined: Dec 2007
Posts: 18,160
Mass
DAYCLONA
I Live Here
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I Live Here
Joined: Dec 2007
Posts: 18,160
Mass
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Quote:
I have been working on my vibration problem which I believe is coming from the drive line angles being off on acceleration it's bad and on braking it's worse around 30 to 40 mph.
I have found that the tranny is 2* down, the driveshaft is 3.5* down and the rear end is 0* so I believe I need a set of 2* shims to get the rear end up to the exact opposite of the tranny.
Am I correct in thinking if I make a 5" long shim with a 2* angle it would correct the rearend angle or does anyone have a set they can measure for me.
No mention of the vehicle?...I'll assume your working on a 66-72 Mopar?, leaf spring equipped?...if so, be aware the Mopar rear pinion rotates upward on acceleration, anywhere from 2 to 4 degrees, seeing that your engine/driveline angle is 2 degrees tailshaft down, and your pinion is 0, you should start with a 2 degree shim, POINTING THE PINION NOSE DOWNWARD, so that upon acceleration/forward mode the pinion will rotate upwards to no more than 2 degrees NOSE UP, putting it on a parallel with the engine/driveline, this should also yield you a 1 degree or more u joint angle deflection which is the minimum required for proper u joint orientation....
When most see this driveline orientation pic, what is not mentioned, is that this is the ideal configuration at ACCELERATION where the pinion is rotated
Mike
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Re: drive line geometry shim specs
[Re: OldMoparMan]
#1419333
04/14/13 01:56 AM
04/14/13 01:56 AM
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Joined: Mar 2013
Posts: 197
Nor-Cal
loaderpro
member
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member
Joined: Mar 2013
Posts: 197
Nor-Cal
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Here is an easy way to measure, Under no circumstances should the pinion ever be allowed to rotate to a positive angle! The easiest way for a novice to set pinion angle is to get an inclinometer, about 20-25 bucks at most hardware stores. Jack the car up and support it, the rear end must be at ride height, level the driveline to zero, now put the inclinometer on a machined surface such as the pad where the pinion snubber sits and read the number. With the driveline at zero, set the rear end as follows,
5-8 degrees negative, leaf springs
2-3 degrees negative, ladder bars
1-2 degrees negative, 4 link
You state you have 3.5 degrees of driveline angle and a zero pinion which gives you 3.5 degrees of pinion angle, so a 2 degree shim would put ito the ball park, if it is a high torque combination then put in a little more shim.
Remember, Pinon angle is set for the pinion in relationship to the drive line, not what comes out of the transmission.
Ideally you would like to see zero degrees under load but the results for this are very minimal and not worth a lot of time.
Last edited by loaderpro; 04/14/13 02:19 AM.
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Re: drive line geometry shim specs
[Re: OldMoparMan]
#1419334
04/14/13 10:30 AM
04/14/13 10:30 AM
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Joined: Feb 2004
Posts: 1,012
indiana
mcmopars
super stock
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super stock
Joined: Feb 2004
Posts: 1,012
indiana
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Quote:
I have been working on my vibration problem which I believe is coming from the drive line angles being off on acceleration it's bad and on braking it's worse around 30 to 40 mph.
I have found that the tranny is 2* down, the driveshaft is 3.5* down and the rear end is 0* so I believe I need a set of 2* shims to get the rear end up to the exact opposite of the tranny.
Am I correct in thinking if I make a 5" long shim with a 2* angle it would correct the rearend angle or does anyone have a set they can measure for me.
leave it alone,you are good where its at.see dr diff if you dont believe
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