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Old 08-27-2008, 05:07 AM
Hellbilly Hotrods
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after installing what are supposedly belltech 3 inch drop leaves in the back of my truck, i have come across a vibration in top gear, cruising, at speeds of 50 or greater. its bad enough that i can watch the bed rock in my side mirrorrs. i have just finished measuring angles, and now im unsure what to do with them.
i used an angle finder from lowes, and measured using a 3/4 short socket from the u-joint caps, with the cap being perfectly centered at the bottom of the driveshaft. the angles are:
front, yoke: +4
front, Drivehsft: -1
Rear yoke: +3
Rear driveshaft: -1

and as far as the numbers themselves are concerned, my math gets me to + 3 front, and +2 rear. if what im reading all over the place is right, i wnat to bring my rear down to -3, correct? equal but opposite? so that would mean 5 degree pinion shims.

am i way off base here?

ive read all sorts of websites and articles on driveline angles, and get more and more confused with every one i read. and i suck at math and geometry to begin with. so can someone boil it down to the level of moron for me, that way i can start to understand it all?


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Old 08-27-2008, 10:20 PM
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lets bump this back to the top.
Dont worry how old you are... it is the mileage on your body that adds up.
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Old 08-28-2008, 04:55 PM
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The idea with the driveline is to not have any u-joint running with more than 2 deg out of straight. I think your math is correct.

In your case I would tip the pinion down 2 deg. I think that would straighten things out and quiet the vibration.

I may be wrong too. But I took the same approach as you on my two piece drive shaft and it quit vibrating and I was not able to get nearly that close.
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Old 08-29-2008, 07:03 PM
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is the drive shaft to far in to the back of tranny now banginig on the taleshaft bushing or in case of 2pc shaft tearing out the center support bearing... might have to shorten shaft...
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