hey guys, I am rebuilding a driveshaft for my JK and I would like to compare with what people are currently running.

I ignore what brand it is, and everything else. my friend broke it last spring and it appeared to be too long for his jeep. Now, I have cut around 2" of the tubing, and with about 4.5" of lift I have 3" flush of the splines showing, out of 7" total. Is that too much? If we think that when the suspension drops, the driveshaft will shorten, I should be ok just like that.

2014 jk with NAG1 auto transmission.

 

As the suspension drops, the driveshaft will get longer.

 

What he said. That's about how much I normally have showing of the "splines" sitting at ride height (2-3 inches). Same lift height at 4.5".

 

the driveshaft gets shorter as the suspension drops.

 

false, it gets shorter. Do some research.

I am a chrysler tech, and have modified many jeeps in the last 4-5 years, and I know what I'm talking about.

As the suspension drops, the diff moves in an arc pattern, the more it goes down, the shorter the driveshaft will get, and the opposite is also true, as it moves up (suspension collapse) the driveshaft will get longer. This phenomenon is less prononced with long arms, which is one of the benefits of running long arms.

so that said, let the comparisons continue

 

On a short arm set up the driveshaft will shorten at droop and extend at stuff if your control arms are not parallel to the ground at rest. On a long arm the driveshaft may get longer depending on the length of the control arms and the mounting locations.

This is due to the tighter arc the control arms travels in in relation to the driveshaft which is much longer then the control arm. AS the suspension droops the axle is pushed towards the center of the jeep and reduces wheel base.

Placing the splines at center will be fine for what you are doing. How are you planning on balancing it?

 

Could not explain any better, thanks.

And as for the balancing, I will try the ol' school method, try and error with pipe clamps, otherwise I'm gonna have to bring it to a shop, but it costs like 100$ only for the balancing

I will get the ballstud yoke welded by a machinist too, this way I'll be sure that if I get vibration, that its not the yoke that is not welded properly.

 

I did not see mention of LA's so i went with shorter lol

 

Yeah, didn't think about the arcing of the axle. It'll depend on how the setup is. Super high lift with a large slope to the diff will shorten when it collapses (think 6"+ lift with a large slope to the diff on a arc, the slope decreases as the diff/axle moves about the pivot points of the control arms and shaft has to shorten, and vice versa). A near zero slope/somewhat OEM look, it'll do the opposite and lengthen as the diff/axle is now arcing away from the t-case when the suspension collapses. Good call of "false" Mr. Dwight (holeshot) from the office. ...it depends.

 

actually I'm at 4.25", and a couple friends are around 5, 5.25", and it gets shorter too..