[Fropleyqk]

Excellent write up. Shed a lot of light on things for me. Thanks.

[Unlimited04]

Updated to include a few more pictures and this section: When a Rear Double Cardan Shaft is Typically Required

[JeeperFound]

Excellent write up!!

[Unlimited04]

Originally Posted by maaghimself

Anyone ever wonder why they put the fixed yoke with the double cardan shaft on the front with the longer (and less steep) driveshaft angle, and put the slip yoke on the rear of the transfercase and coupled it with a ridiculously short drive shaft?

I believe you can rationalize this one by noticing the front axle flexes more than the rear and the front axle's pumpkin is offset. When the rear axle articulates the pumpkin stays fairly centered, but when the front axle articulates the pumpkin travels a much larger distance - causing a more severe driveline angle when the drivers is at full droop.

[tuc]

Great artical. At first I though this was about cv axle shafts like the RVC Performance which are the same as the longfield shafts, now if you have any insight on those that would be great. but still good read

[Unlimited04]

Originally Posted by tuc

Great artical. At first I though this was about cv axle shafts like the RVC Performance which are the same as the longfield shafts, now if you have any insight on those that would be great. but still good read

so as I described in post #1, CV's are Constant Velocity joints. A true CV axle would be an axle shaft with a CV joint in it.

Like this front wheel drive application:


Remember they work like this:


Notice there is a boot covering the mechanism. Remember, CV axles are stronger for their given size than a U-joint system, which is why they are used so frequently where space is premium - like Front Wheel Drive sedans and Independent Suspension systems.

Strength is always about two things - material choice and how much force you put across how much area of that material. CV's are stronger by design - they have more degrees of movement and more surface area to spread torque across. U-joints have two points of contact - each roational axis of the 4-pointed U-joint. Constant Velocity joints have the little ball bearings inside that spread the same force across a much greater area - think of it almost like a multiple-pointed U-joint.

The major downside to CV axles in a TJ is they will most likely require some grinding or knuckle modifications and they are EXPENSIVE.

But since we're talking about drive shafts here, read this thread and start another if you feel the need -
http://www.jeepforum.com/forum/f9/front-cv-axles-rubicon-i-got-some-649714/

[JerseyDubbin]

awesome writeup. Explained a lot to me.

I wish they had a rep system so I could add a rep to you.

[ZBDsTJ]

Very informative and well presented. Well done, sir, well done!

[GregB_00XJ]

Excellent write up and awesome pics!

[tuc]

Originally Posted by Unlimited04

But since we're talking about drive shafts here, read this thread and start another if you feel the need -
http://www.jeepforum.com/forum/f9/front-cv-axles-rubicon-i-got-some-649714/

nope no need to start another thread, you seem to know alot about these things and was just picking at you brian alittle trying to learn more

oh and thanks for the link

[Peterpsc]

Outstanding. Thank you.

[explorerlyon]

Outstanding!!! I have been reading all over the internet to try and understand this stuff and just got more and more confused. You're write up is perfect!

[jgorm]

great job!

[mouse]

Ok I have a question. So since an LJ has a longer wheel base at what point will a Slip yoke eliminator and DC be required? How much lift?

[jgorm]

Originally Posted by mouse

Ok I have a question. So since an LJ has a longer wheel base at what point will a Slip yoke eliminator and DC be required? How much lift?

Example:
- A 2.5" lifted SWB NV231J equipped TJ will most likely experience vibrations. A small transfer case drop will fix this.
- A 2.5" lifted LJ (LWB TJ) with a NV231J will NOT experience vibrations. No SYE or transfer case drop will be necessary - the driveshaft is long enough the driveline angle is not as severe.
- A 2.5" lifted SWB or LWB NV241J equipped TJ/LJ will most likely NOT require a Double Cardan Shaft. The shorter transfer case allows for a longer driveshaft - less severe angles.
- A 4" lifted NV231J TJ WILL require a SYE or large transfer case drop.

I would figure this to mean that you would need one if you go over ~2.5"