Front double-cardan upgrade - yay or nay

[Adrian D]

The rzeppa joint at the transfer case recently failed on my CRD.
I've heard mixed reports of the aftermarket rzeppa life so I looked into the double-cardan upgrade.

Any cons to a double-cardan conversion? The car is at stock height and upgrade cost is minimal as I can get the parts cheap.

Who here has done the upgrade? Any difference in vibration at highway speeds?

[Hayesio]

CV joints are smoother and stronger. They are expensive, but if you get them from Rock Auto wont be too bad. U-joints are cheaper and better for lifted vehicles. Even with a double carden the U-joint shaft wont be as smooth, but will be fine. If you go for a double carden, make sure you get one with a releasable bulk head, this is the part that tends to fail.

[bodgie]

Originally Posted by Adrian D

The rzeppa joint at the transfer case recently failed on my CRD.
I've heard mixed reports of the aftermarket rzeppa life so I looked into the double-cardan upgrade.

Any cons to a double-cardan conversion? The car is at stock height and upgrade cost is minimal as I can get the parts cheap.

Who here has done the upgrade? Any difference in vibration at highway speeds?

If you keep it greased it will last way better than the rezeppa. Pretty good reason to upgrade to me.

Jason

[JeanLuke]

Are you talking front shaft or rear?

I'm curious because the rzeppa joint on my rear shaft has started to leave a grease stain under the floor. I think it's days are numbered.

[Adrian D]

Originally Posted by Hayesio

CV joints are smoother and stronger. They are expensive, but if you get them from Rock Auto wont be too bad. U-joints are cheaper and better for lifted vehicles. Even with a double carden the U-joint shaft wont be as smooth, but will be fine. If you go for a double carden, make sure you get one with a releasable bulk head, this is the part that tends to fail.

What do you mean by bulk head? This piece?

Originally Posted by bodgie

If you keep it greased it will last way better than the rezeppa. Pretty good reason to upgrade to me.

Jason

I'm looking at the double cardan option because of the bad rep the replacement rzeppa's available here.

Originally Posted by JeanLuke

Are you talking front shaft or rear?

I'm curious because the rzeppa joint on my rear shaft has started to leave a grease stain under the floor. I think it's days are numbered.

Front. Mine failed on the way back home from a long trip, so I had to take it off in the middle of the night.

[bodgie]

The double cardan joint has two uni joints plus the centering yoke pictured, that all need regular greasing. The driveshaft is rotating pretty quickly so there are a number of components that will see a lot of operations under normal use, if you wondered what this looks like there is a pretty good animation.

https://grabcad.com/library/double-cardan-joint-1

You can buy after market rezeppas that are good quality, however, if your Jeep is even moderately lifted the transfer case end angle will wear the joint out pretty quickly. The boot fails first and creates the major source of wear.

Jason

[Hayesio]

Yes, thats the bulkhead bearing. Many manufactures leave out the grease nipple on this. And when they let go, they really let go! It will probably happen at highway speed and destroy the bearing in your transfer case. The good news is they generally give you plenty of warning, bad vibration, squeaky etc.