Another driveshaft question

[ryno56]

I was going to post this in the driveshaft length thread but that's all about stock trucks...

 

So, I've swapped an AX-15/NP231 and Chry 8.25 from a '98 XJ into my '90 MJ SWB and after reading the driveshaft length thread I decided I should need a 42.25" ds. Easy enough.... Learning as I have to always double check, I measured the eye to eye under my truck with the slip yoke in the original position and the truck on its wheels. I come up with ~40" :huh???: . That's not even close! I'm having it made to that length 'cuz that's what's gonna fit, 42.25" would definitely bottom out on the TC before getting the U-joint in place.

 

Did the change from the external to internal seal on the NP231 change this or is there something else I'm missing?

[ryno56]

any one else ever seen this issue? I couldn't find any info on XJ ds lengths to cross reference.

[Pete M]

XJ driveshafts will be about 12" shorter than an shortbed MJ with the same drivetrain.

 

 

and I don't have any numbers on it, but it very well could be the sealed t-case that's causing the discrepancy.