New driveshaft decision

[chipflyer]

I have recently replaced the T-150 in my 78 CJ7 with a T-18 , which has a 4" lift and will now need a rear driveshaft that will be shorter. I am dropping the Transfer Case down with shims between the skid and frame as it would have been from the factory. With the standard stock driveshaft I had no issues before the swap with u-joints or vibrations. Since my angle is going to be a bit steeper maybe I should consider a double cardan style driveshaft? Here is a little drawing I made with my specs, I would appreciate any thoughts from guys who understand the math. I know it would be easy to just spend double the money and go with the double cardan driveshaft but just wonder if its really necessary. The drawings measurements are right on and I just wondered based on my numbers if it was obvious that I should lean one way or the other.
Thank you

 

[hole]

Tom Wood's Custom Drive Shafts - Tom Woods Custom Drive Shafts Custom Driveshafts Specialist

This might help

 

[gert]

Tom Wood's Custom Drive Shafts - Tom Woods Custom Drive Shafts Custom Driveshafts Specialist



This might help

X2 for sure, my rear driveshaft is a double cardon Tom Woods


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[Torxhead]

I installed a T-18 in my '86 CJ. For the rear driveshaft I used the oem shaft with a heavier tube and shortened it to accept a double cardan u-joint. When I installed the tranny, it was mounted as low in the rear as I could get it. The rear pinion angle was pointed directly to the driveshaft angle. The diff was welded in that position to eliminate shims and there is no Transfer Case skid plate drop.

 

[mriplaybass]

Definitely Tom Woods. I lifted my entire drive line to a 2° down angle to get more belly clearance, and rotated and welded the rear axle spring perches to point at the Transfer Case yoke. Runs smooth as silk.