Possible driveshaft or pinion angle issues

Stop quoting specific angle numbers, they are irrelevant and both will change as you raise or lower the pinion angle.

If your pinion angle is obviously lower than the driveshaft angle is, keep raising the pinion upward until it is the same as the driveshaft.
 
Stop quoting specific angle numbers, they are irrelevant and both will change as you raise or lower the pinion angle.

If your pinion angle is obviously lower than the driveshaft angle is, keep raising the pinion upward until it is the same as the driveshaft.

Ok, so I'm lowering the pinion to achieve this or raising it so that its close inline with the driveshaft? Once again, sorry for being dumb.
 
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Exactly. Just make it look like the illustration in previous post #12 here. :)

Starting to make sense, I'm thinking I was paying way too much attention to rear factory draiveshaft photos and looking at mine and thinking, there is no way these measurements will ever equal but the front is a CV type, not the standard as it is in the rear from the factory.
 
Wait, I confused us both by having incorrectly thinking you were talking about your rear pinion angle. I looked again and determined you were asking about your front axle. What I said was all true where the front axle is concerned since your front driveshaft has a DC joint.

But all this would be incorrect for the factory rear non-DC rear driveshaft, though it would be correct if the rear driveshaft has been upgraded to an aftermarket DC style driveshaft. What is installed in the rear? Is the stock driveshaft still there or has it been replaced with an aftermarket DC driveshaft. If your rear driveshaft is still stock then the angles I have described above would all be incorrect for the factory style non-DC rear driveshaft.

This drawing is correct for the standard non-DC rear OE driveshaft as the factory installed in the rear. Its pinion angle needs to be the same as the angle of the transfer case output shaft angle... aka parallel to.

2joint_angle.jpg
 
Wait, I confused us both by having incorrectly thinking you were talking about your rear pinion angle. I looked again and determined you were asking about your front axle. What I said was all true where the front axle is concerned since your front driveshaft has a DC joint.

But all this would be incorrect for the factory rear non-DC rear driveshaft, though it would be correct if the rear driveshaft has been upgraded to an aftermarket DC style driveshaft. What is installed in the rear? Is the stock driveshaft still there or has it been replaced with an aftermarket DC driveshaft. If your rear driveshaft is still stock then the angles I have described above would all be incorrect for the factory style non-DC rear driveshaft.

This drawing is correct for the standard non-DC rear OE driveshaft as the factory installed in the rear. Its pinion angle needs to be the same as the angle of the transfer case output shaft angle... aka parallel to.

View attachment 359630

Right, so the rear is factory still which yes it is conventional two joint drive shaft type and then the yokes or whatever both in the transfer case and axle would have to be parallel in measurements, angles, etc.. However, I was referring to the front driveshaft; which is why I thought why I'm getting little vibration since all steering checks out, tires check out, etc..

In regards to FRONT DRIVESHAFT and angles, correct me if I'm wrong, but it is a CV type driveshaft which would mean that have to align the driveshaft with the axle yoke per photo in post #12. Currently, the front driveshaft and axle yoke sit in position similar to Conventional Two Joint Drive Shaft which would mean I do need adjustment, because the shaft and yoke are not aligned. Possbly why the vibration at 45-50. :D
 
It gets a bit complicated with the front axle. The front axle needs to have enough pinion angle to satisfy the requirements of the DC joint but it also needs to give enough Caster angle so the Jeep will track well on the highway without being twitchy. Having enough Caster angle is not as critical as having the correct pinion angle to keep the DC joint happy though in the case of front axle, pinion angle (to keep the DC joint happy and vibration-free) trumps Caster angle. It's more important the front pinion angle not be excessive so far as the DC joint is concerned which will cause driveshaft (u-joint) vibrations.

Someone dialing in plenty of Caster angle to assure good highway tracking characteristics might have given too much importance to the Caster angle which has created an excessive DC u-joint angle that will cause vibrations.

The rule-of-thumb is to increase the front axle's caster angle to the point it causes driveshaft (u-joint) vibrations and then back it off enough to stop the vibrations. Pinion angle trumps/is more important than caster angle. And they are directly connected... increasing one decreases the other. One cannot be changed without affecting the other.
 
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It gets a bit complicated with the front axle. The front axle needs to have enough pinion angle to satisfy the requirements of the DC joint but it also needs to give enough Caster angle so the Jeep will track well on the highway without being twitchy. Having enough Caster angle is as critical as having the correct angles to keep the DC angle though in the case of front axle, pinion angle to satisfy the DC joint trumps Caster angle. It's more important the front pinion angle not be excessive so far as the DC joint is concerned which will cause driveshaft (u-joint) vibrations.

Someone dialing in plenty of Caster angle to assure good highway tracking characteristics might have given too much importance to the Caster angle which has created an excessive DC u-joint angle that will cause vibrations.

The rule-of-thumb is to increase the front axle's caster angle to the point it causes driveshaft (u-joint) vibrations and then back it off enough to stop the vibrations. Pinion angle trumps/is more important than caster angle. And they are directly connected... increasing one decreases the other. One cannot be changed without affecting the other.

I see, I'm thinking looking at my caster #s and angles of the shaft / axle I might try to equal out the shaft and axle, but watch my caster. Everything I read so far, I should be closer to 6 on caster then being 7.7 which is why I get a bit of a vibe at 45-50 I'm thinking. So I might go on caster down to 7 and see how the angles look on the shaft and yoke / axle. Then do a test drive and see if that went away.
 
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I see, I'm thinking looking at my caster #s and angles of the shaft / axle I might try to equal out the shaft and axle, but watch my caster. Everything I read so far, I should be closer to 6 on caster then being 7.7 which is why I get a bit of a vibe at 45-50 I'm thinking. So I might go on caster down to 7 and see how the angles look on the shaft and yoke / axle. Then do a test drive and see if that went away.
6 degrees of Caster angle is more than fine for factory size or 30-31" tires, 7 degrees is the factory angle but its acceptable range is +/- 1 degree. And the bigger the tire the less caster angle that is required to have good highway tracking. Like for 35's 5 to 5.5 degrees is enough.

Trying for 7.7 degrees of caster angle is far more likely to cause driveshaft vibrations by causing an excessive pinion angle for the DC joint.
 
Well, got under there and obviously no adjustment bolts had to borrow them from the other TJ which is parked for now. Anyways, installed those and changed drivers C from 7.7 to 5.5 and passenger to 6 to deal with the way roads are constructed. I think I've read somewhere that I should add .5 extra on the passenger. Correct me if I'm wrong. :)
 
Well, got under there and obviously no adjustment bolts had to borrow them from the other TJ which is parked for now. Anyways, installed those and changed drivers C from 7.7 to 5.5 and passenger to 6 to deal with the way roads are constructed. I think I've read somewhere that I should add .5 extra on the passenger. Correct me if I'm wrong. :)

How can you adjust the left and right side castors different?
 
Maybe the adjustable cam bolts but I think they only give a degree or so of adjustment.

Right, they give about 3 degree of adjustment max. I usually get about 2 and its not perfect but I went from 7.7 to like 5.8/6.0 ... having a hard time giving passenger side extra .5 because no matter what I do to passenger side its more then the driver and that is because the driveshaft keeps it more in place then the passenger side does. So, I tuned the driver side with the adjustable cam bolt and then matched the passenger side to the same. I know it'll pull little to the right because of how roads are built but I'd rather have that slight pull then vibrations.

But to answer the adjustment left and right, each lower control arm by the axle bracket has adjustable cam bolts. I believe 2000+ don't, so you'll have to buy them and replace the factory bolts with those. Then you are able to adjust by turning the bolt with your socket wrench 3 degrees.
 
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I am still confused. Unless your C-arms are welded on at different angles, the left and right castors have to be the same. Or am I missing something?
 
I am still confused. Unless your C-arms are welded on at different angles, the left and right castors have to be the same. Or am I missing something

both sides have or you need to buy these bolts with washers like in the picture. Its on both sides like that so you can adjust one angle higher then the other, not by much but still.

IMG_0082.jpg
 
both sides have or you need to buy these bolts with washers like in the picture. Its on both sides like that so you can adjust one angle higher then the other, not by much but still.

View attachment 359753

You are missing the guides on the side of the cam bolt that allow the bolt and cam to rotate about the larger center hole. If you turn that, the bolt and cam rotate around each other, not giving the offset you need.
 
You are missing the guides on the side of the cam bolt that allow the bolt and cam to rotate about the larger center hole. If you turn that, the bolt and cam rotate around each other, not giving the offset you need.

Yeah not my photo and I didn't notice that, good catch. Yes there are guides for these on the brackets and 2000+ jeeps don't come with the adjustable cam bolts, so you got to get a set.
 
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