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Discussion Starter · #1 ·
I've read that the idea situation would be to have the angle of the trans output shaft and pinion shaft should be equal and offsetting - that is, whatever angle the trans is pointed down then the pinion should be pointed up the same amount. My question is, how much difference in allowable between the two angles.
 

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Discussion Starter · #2 ·
I've read that the idea situation would be to have the angle of the trans output shaft and pinion shaft should be equal and offsetting - that is, whatever angle the trans is pointed down then the pinion should be pointed up the same amount. My question is, how much difference in allowable between the two angles.
 

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Discussion Starter · #3 ·
I've read that the idea situation would be to have the angle of the trans output shaft and pinion shaft should be equal and offsetting - that is, whatever angle the trans is pointed down then the pinion should be pointed up the same amount. My question is, how much difference in allowable between the two angles.
 

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An angle of around 1-3 degree's at RH under normal light loads allows the U joint bearing to rotate and redistribute the grease for a long life. When you get into 10-30 degree OR when the driveshaft/transmission output/rear axle are perfectly inline you get into having to check them more often for wear.
 

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There is a ton of opinions on this and they will go the same way as the ported vs full manifold vacuum argument.

Once or twice a year I get involved in using an Eaton driveline analyzer program due to vibration in class 8 trucks. There is an acceptable amount, but the amount that leads to a perfect setting, according to Eaton, is they both need to be the same as long as the driveshaft is not the same angle. There is a point where the difference between the yokes and driveshaft is too much, but in a normal ride height car it will never be too far.

For example, the transmission at -3 degrees, the driveshaft at -5 degrees and the pinion at -3 degrees is considered perfect. I set all of mine to within a degree of the same for the trans and pinion. And never have had an issue with this - no vibration, no excessive wear and very easy. This works for daily drivers and 800hp.
 

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Depends on the rear suspension. If you are running leaf springs then you must account for the pinion walking up the ring gear and causing the pinion angle to change. Say the trans is 3 degrees down, then the pinion in this case should only be about 1 degree up. Triangle 4 bar and parallel 4 bar will not change so match (offset) the pinion to the trans.
 

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I've built all of mine (that sounds like a lot, but probably half a dozen) between 1-4 degrees. Trans and pinion parallel and opposite, and between 1-4 degrees of angle between the flanges and the driveshaft. You need some angle to keep the lube moving in the u-joints, but more than 4 and you may get vibes. Even if you don't get vibes, you're asking more from the u-joints than needed.
 
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