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Drive Shaft Angles

Posted: Thu Dec 14, 2023 7:08 am
by Jevman
I'm looking at fine tunning my front drive shaft angle with a double Cardan or is it just called a Cardan? Front axle is at 12.9 degrees, transfer case is at 5.9 degrees up, drive shaft is at 16.8 degrees after the double Cardan. The numbers in green in the photo is where I am trying to go, I can clock the transfer case one more hole to see if it will bring it into a closer range to the green numbers that I'm trying to get to, what I'm asking is, am I on the right track here in clocking the transmission and not shimming the axle and is this the right way to do it?

Re: Drive Shaft Angles

Posted: Thu Dec 14, 2023 7:24 am
by Jevman
Here is a drawing

Re: Drive Shaft Angles

Posted: Thu Dec 14, 2023 9:53 am
by Stuka
Typically, there is a double cardan joint at the t-case side of the front axle. A regular u-joint is a single cardan.

You can't shim the front axle, as that changes the castor angle of the steering knuckles. Pointing the pinion up will make the Jeep near undrivable as the tires will not self center.

But having a different angle at the pinion than the t-case is ok when you have a CV (double cardan in this case) on the t-case side.

How much lift do you have? Normally, a double cardan on the t-case side is fine. But if you have an SOA up front or something, you will likely want a double cardan on both sides of the drive shaft.

Re: Drive Shaft Angles

Posted: Thu Dec 14, 2023 10:04 am
by Jevman
I have a 4" lift on it with the double Cardan on the transfer case side right now

Re: Drive Shaft Angles

Posted: Thu Dec 14, 2023 4:40 pm
by Yeller
You’re not out of what is acceptable angles. It’s a lot of expense and work to correct the pinion angle. Clocking the case down makes a significant difference, but the sacrifice is ground clearance.

I would do 1 of three things.
1, remove the front axle, cut and turn the C’s to add 15* of caster, machine the cast spring perch 11 degrees to raise the pinion and replace the tube side spring perch to be correct.

2, repeat the cut and turn of the C’s to add caster and link it and do away with the leafs to correct the pinion angle.

3, leave it alone.

I’d sway between 1 and 3. If I was happy with the ride and handling, 3 if not then 1.

Re: Drive Shaft Angles

Posted: Fri Dec 15, 2023 3:56 am
by Jevman
The transfer case is sitting just about where it should be right now on clerance so maybe I should wait and drive it first once it's done, it's just so easy to clock the case while the body is off, Thanks for the Info Guys!