Since I'm looking to lift a bit more and will probably buy a new rear drive shaft, I was looking around and in the Q&A thread WOL says that if you are swapping out the rear drive shaft that you will also need to buy adjustable rear upper control arms. Is this the case? or can i get buy with just buying the driveshaft? If it matters I will be getting the front lower control arms as well, I just dont want to spend the extra money for rear upper control arms too!

 

come on people....i know those with 2drs have switched driveshafts....

 

WOL tells no tales.

Yes it is true.

David

 

if I will be getting front lower controls arms anyways will these allow me to adjust the pinion enough to fit the aftermarket rear drive shaft in? or is it necessary that I get both the front lowers and rear uppers?

 

You will need Rear Uppers , The front Lowers do nothing for the rear.

David

 

ugg this is gonna get expensive real quick damn jeep is emptying my every pocket!

 

i am also looking into getting a rear driveshaft and was wondering if the lift size matters. i have looked online at many driveshafts and noticed a few that listed for 4"-6" lift. i have a 4" lift by the way. most of the ds i saw didnt mention anything about lift height though. do i need one that says for lifted jeeps 4" or more? sorry to hijack the thread i also wanted to know about the ru control arms as well. its crazy how if you spend money on one thing you have to buy 3 others things to make the original work!

 

Hi 07Rubi2dr,

I can only go by what I have read and been told.

If the rear OEM shaft is replaced with a custom shaft with a traditional U-joint at the differential and a CV (double U-joint arrangement) at the transfer case, the pinion angle must be set such that the angle between the pinion and the driveshaft is as close to 0 degrees as possible (to allow the single U-joint to operate reliably). I believe that 3 degrees is the maximum recommended difference.

I installed new driveshafts on both the front and rear. I didn't want to be concerned about failure, knowing it would likely happen at some point in time.

I am concerned, at least a little, about the pinion angle on the front differential. Because the control arms in the front (upper or lower, depending on your set-up) are used to set the caster, you really don't have much left to control the pinion angle. If I understand the suspension factors correctly, the front driveshaft is normally treated like a red-headed stepchild (no offense meant to any red-headed step children, or their relatives). Basically, the caster is generally set to a maximum that appears to be limited mainly by the front driveshaft vibration issues caused by too much of a difference in angle between the pinion and the driveshaft. If I am off-base, someone please correct me.

But, perhaps because the front driveshaft and differential are "normally" used for slower speed excursions, it is considered a general, acceptable risk to run a greater angle between the pinion and the driveshaft.

There has been at least one thread recently in which double CV driveshafts have been discussed. I believe that these were in reference to front drivelines. I'm not quite as certain about what I am about to say as I would like to be, so I hope someone with more knowledge will correct this reference if it is wrong, too. In the case of double CVs, I believe that the output of the transfer case and the differential should be parallel, and that the maximum angle between the driveshaft and either of the other two should be 15 degrees under normal circumstances. (Even with double CVs, I still question the pinion angle caused by adjustment of the caster, and the fact that the pinion angle and the output of the transfer case will never be equal. I can see someone reworking the mounts for either the upper or lower control arms so that the pinion angle and the caster could be set correctly; but, I have never read about anyone on the board doing this. Is the double CV more forgiving?)

This really is meant as an absolute explanation, but moreso as a statement of the confusion that exists about this topic. For the time being I have single CV driveshafts for the front and the rear. I would sure like to know if the front is really set up for long term reliability.

Good Luck

Jeff

 

Hi welker-jk,

Most fabricators will ask for measurements between the pinion and the transfer case output.

I am second-guessing myself because I didn't plan far enough ahead.

I may not go higher than the 3+" I got out of the OME LT kit; but, I may.

Before I ordered the Tatton shafts I should have recorded the measurements for the 3" and then figured out how much higher I may go. (Maybe one or two inches max, I believe.) I could have then provided that information to Curtis Tatton and asked him to optimize a shaft between the two.

If you can measure your current driveline requirements, and identify any additional lift preference at the time you order your new driveshafts, you may be able to get away with buying shafts one time only. I suspect that there may be situations where the difference in lifts may be too great, and two sets of shafts will be required. I would hope that the fabricators could tell you exactly.

I hope this helps.

Jeff

 

interesting thanks for the help Jeff09

I think I'm gonna just go for the LCA and forget about doing the driveshaft for now...i should be hovering right around 3" of lift so hopefully I can stick with my stock drive shaft for a while as I dont really want to spend the extra coin right now on rear upper CA's as well as a new driveshaft!