Misc Has anyone shortened their rear driveshaft, and how much shorter is working for you?

[CJ27]

I want to use a longer Transmission and xfer case combo. I really like taking advantage of my CJ7 's great turning radius, so I prefer not to stretch the wheelbase any more than I would have to. I'm guessing some of you have done similar mods. I'm wondering how much shorter the rear driveshaft could be before it would cause more problems than losing some of my beloved turning radius.
Has anyone shortened their rear driveshaft because of modifications like a longer Transmission or Transfer Case ? Has anyone shortened one enough to cause any issues?

 

[CJ]

It is quite common to need to run a shorter rear drive shaft when swapping equipment in your CJ7 .
Just be sure you correctly set your drop and pinion angle.
Also be sure and use a double cardan shaft.
There are many places that will make one for you.
Tom Woods is highly recommended and they have great information on setting up your angles.

Custom Drive Shaft Shop | Tom Wood's Custom Drive Shafts

Trail Tested, Competition Proven, Show Quality Driveshafts and Slip Yoke Eliminators for Jeep Wranglers, Cherokees, Ford Broncos and more.

4xshaft.com

 

[TSB8C]

I did shorten mine when I installed the 700R4 auto Transmission , Novak adaptor, and Dana 300 Transfer Case . I needed to go about 3 inches shorter than stock, at 22.5" eye-to-eye. I also have a 4" suspension lift. So shorter drive shaft plus steeper angle = no bueno. So I installed a drop kit for the Transmission and Transfer Case - basically spacers that drop the skid plate down a bit from the frame. This angles the output of the transfer cases down a few degrees. I also had shims on the rear axle spring mounts to slightly angle the pinion upward, but custom ordered angled mounts welded when I got the new rear axle form ECGS. CJ is right with the recommendation of a double cardan shaft, but I didn't need one with my setup. I easily cruise 75mph on the highway with no vibration issues at all. If you're not familiar, here's a double cardan shaft (two u-joints at the left end in the pic).

 

[CJ27]

Thanks, that's very useful information. It will be a while before I can calculate all the new positions for everything, but I'm very glad to know that losing 3" of length could still work if I can get all the other angles right.

 

[TSB8C]

 

[KRUPP]

Good info, for sure.

Considering cost - Happen to be pricing out a new front driveshaft this week for my early Bronco project. Looking for same as Woods picture above with dbl cardan on one end and full length slip.
Solicited several places, even local shop, and Woods was the cheapest by $50 or so. The free shipping helps.

You’ll be able to reuse your current shaft though, so you might just drop by a local shop.

 

[CJ27]

I am planning on switching to the double cardan once I have the length calculated and measured. I also want to try to see if the shorter driveshaft will become the limiting factor for axle movement. Since it will be a while before I learn enough to be confident with the Transmission swap, I'll just fix some of the miscellaneous stuff that has been on the wait list for years.