agreif

iTrader: (4)

You beat me to it, I just posted in the other thread that I assumed the angle of the pinion didn't change when doing the shackle, but what you are showing makes sense, I would need fat end backward.

My problem still is that my pinion still points at a greater angle upward than my DS, so I still have a + pinion when all the reading I've done says it should be 0 or negative. Maybe my setup was somehow wrong from the beginning. I agree with you though, that, in theory I should just be putting the fat end backwards. I'm just gonna put the stockers back on this weekend, measure and make sure the shimmy is gone. Then put the drops back on and get the same angles. I'll post back on Monday. Thanks for straightening me out though.

Colby 04

Hey no problem. I think you may be stressing the value of the angle too much - the main thing that has been stressed is that there is no vibration.

Grey Silver

iTrader: (1)

My trans is -3 and that's a good thing because it sits about 3" higher than the rear end so it's pointed down. trans -3, pinion +3 = 0. For your truck -2 would be ideal. Under acceleration the pinion angle goes +. The u-joints do the least amount of work when the faces of the yolks are parallel. When the u-joints have to work too hard it causes vibration.

BigCountryx

iTrader: (3)

U-joints cause vibration when the angles front and rear (tranny and pinion) are different because at a given angle the u- joint causes a vibration. The opposing u-joint which is at the opposite end of the shaft and is in phase basically cancels out the vibration with an opposing vibration. If they don't match closely, they will not cancel each other out and you will feel the vibration. That's the way I understand it.

Colby, I do dispute your theory to a point. Not saying it is totally wrong, but your picture does not take the rest of the driveline into account and only focuses on getting the pinion back to the stock angle. Yes the pinion is rotated down, but in most cases, it needs to be. I can promise you that there are trucks that have shackles only installed and still have a high pinion angle, which is opposite of what you depict in your picture. Also, to make your image more accurate, you should have not lowered the front hanger and you should have included the tranny in the pic. If the hanger was stationary, then the rotation of the axle would be more accurate and if the tranny was included in the picture, then the relationship of rear pinion to tranny tailshaft could be compared. But, if not to scale, it's pointless anyway.

IMO there are 2 rules to driveshaft allignment.
(1) If you have a standard 2 u-joint shaft, the tailshaft and pinion angles should be within a degree or two of each other (pinion down for axle wrap)
(2) If running a cv shaft, the pinion should point at the tailshaft (of couse down a degree or two for axle wrap)

BigCountryx

iTrader: (3)

The way I understand it, If your Tranny Tailshaft Output were 0* then You would want your Pinion to be around -1* with a standard 2 u-joint, single shaft setup. Like so.

Colby 04

oh I'm sorry it's not to scale and doesn't depict an accurate pinion angle

The point was to show, in theory, what effect the shackles have on the differential - I could give a flying **** less if it's to scale or has accurate real world angles

goodday

BigCountryx

iTrader: (3)

Get as mad as you want, but you are not 100% correct. Your theory is that the fat end of the shim always goes to the back and you pinion always needs to be angled upward because shackles point you pinion down. You are wrong because depending on the vehicle, you may need to angle your pinion even farther downward, or maybe none at all.

And more than being to scale, both angles need to be taken into account not just the pinion angle. that's my point regardless if you give a flying **** or not.

CHEVY6000VHO

iTrader: (2)

I WANT TO SEE SOME MEASUREMENTS OF A 2-PIECE DRIVESHAFT!!!!
DO ALL OF YOU GUYS HAVE A ONE PIECE???
There are quite a few more variables with a 2 piece shaft!

Jim

CHEVY6000VHO

iTrader: (2)

For example: If you have to use a carrier bearing relocator bracket the trans and carrier bearing will not be lined up anymore. Correct?
Then a tranny shim would be needed.
The final tailshaft of course would be lined up like you guys are stating, the carrier bearing acting as the tranny snout.
I will be definetely doing this the right way, and not half *** like most seem to be doing.

Jim

Colby 04

you can point out mistakes in that drawing all day long - it was made in about 10 minutes with ms paint - do you really think I was aiming for it to be drawn to scale and replicate accurate angles? NO

BTW, I'm not mad at all, so carry on whicha bad self