how much spline needs to be in new yoke?

Did a conversion on my cherokee and now have a DS that is juuuust touching the tip of the TC's output shaft. Well, guess I need a new DS, so, how much of the yoke needs to be on the shaft? It was a stock unit but now has 2.5/3" of lift, if that matters, thanks.

no one knows?

Generally, you need 1.5 times the minor diameter of the shaft in spline engagement. However, on a coarse splined shaft, I'd try for at least 2.5 times, usually around 3", to prevent wobble at high RPM's.

My main concern was in and out movement, but, I never knew about wobble problems, thanks crash.

How much should be showing when at rest?

I dont think you go by that. As the trucks suspension goes up and down, the yoke slides on the splines so many inches back and forth. I would think you need to start from the tip of the spline and the tip of the yoke, then, find the right amount that goes into the yoke. I assume, like crash said, you need a mininum of 3", based on his theory and sizes, but, you could have as much spline in the yoke as you like as long as you do not bottom out the spline/yoke combo on full compression, or, have it come apart when the back tires drop out/down.

Now, how much a yoke goes back and forth, I have no idea. I am sure there is some people that can give you a clue, or, it might be burried in here somewhere. I just wish I didnt have 600 projects and more time to hunt for info rather than just yelling for help, but, there just isnt enough time in the day for me, lol....:tears:

To add to this, I was wondering what would be wrong with just lengthening your Drive shaft instead of getting a CV shaft and SYE? It works on Chevy's I have lifted in the past.

chelms27 said:

To add to this, I was wondering what would be wrong with just lengthening your Drive shaft instead of getting a CV shaft and SYE? It works on Chevy's I have lifted in the past.

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It is not the lack of spline engagement that SYE's are fitted. It is to reduce the working angle of the uni's which does not chage at all if you are leaving them still in the same place and just engaging more spline. The double cardon joint also allows the pinion to be rotated up just below the output shaft uni height further reducing that angle along with the fact that a SYE lengthens the distance between the uni's, and what you are saying, does not.

chelms27 said:

To add to this, I was wondering what would be wrong with just lengthening your Drive shaft instead of getting a CV shaft and SYE? It works on Chevy's I have lifted in the past.

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I am sure it would work just fine, depending how high you go. As long as you have the truck compressing, you go from a hard angle to a lesser angle. The real problem lies when your truck gettwisted or has serious rear end drop. Then, the angles get way more exagerated and u-joints start to bind. Just check the DS angle sitting level, then, jack up the from from the back till the wheels come off the ground and then re check the angles. U joints can handle some good angles, thats what they are supposed to do, but, the can only go so far without help.

I just need to know how much on a 2.5" lift I need so the shaft does not come out off of the splines on my truck when it rebounds to the max.