Good Morning,
I "installed" a Hack and Tap from IRO on my 99 with 231 xfer case and have a Front driveshaft to throw in and lo and behold it doesn't fit. My xfer case does not have a drop installed, but it still seems like I am too close from xfer case to the rear. I cut as much off of the output shaft as I could without risking not leaving enough spline. I do need to get actual proper 3.5" inch lift springs for the rear, currently I have some lift shackles. It looks to me like the lift shackles are somewhat rolling the axle forward from it's original location and possibly causing my issue. I am hoping someone has done this before and can tell me if I should be looking into anything other than swapping out the springs to get everything correct.
Does this make sense or am I completely off base?

Also, if anyone has a specific rear leaf pack they can suggest in that range that would be great. I don't want to go super cheap and get something that rides like hell.
Thanks.

 

It doesn't fit because it is not the right length? Or there is an angle problem?
Just trying to be clear
Can you post some pictures?

 

I have the driveshaft completely collapsed and it won't go between the yoke on the transfer case and the yoke on the rear even with the suspension unloaded. I forget off hand what the length is that IRO says to measure to to make your cut but I am under that, because the only way to get it to that length would have required removing all of my splines. It's a length problem, not an angle problem.

 

Have you tried taking the front driveshaft to see if it will fit in the rear ?

 

I just want to be clear that I understand what you're doing.
You said "drop shackles"?
Are you lowering your XJ?
Drop shackles would usually roll the pinion downward.
"Lift" shackles generally rolls the pinion upward, which with an SYE is usually what you want to achieve,
so that the pinion points at the transfer case.
Can you clarify what you're trying to end up with?

 

Yes, that's what I am using.

 

With the shackles on there the jeep is currently lifted over stock. I didn't lower the jeep. That's why I said I intend to get proper 3.5" lift springs.

 

I think he means trying the front driveshaft off your vehicle. To make sure it is 100% the right length and not a driveshaft you think/assume is the right length.

Those are called lift/extended shackles not drop shackles.
are the leaf springs flat or frowning? Is the rear axle pointing at an upward angle toward the floor of the vehicle?

 

My front driveshaft is the same length as the spare one I tried to put in. Neither fit.

I edited the first post so it says lift shackle, I think we have established that they were intended to lift the vehicle. I apologize for calling the shackle that drops the mounting location of the leaf spring a drop shackle.
My stock leaf springs are beat, which is why I need to get proper leaf springs to level everything back out.

My question is whether or not it is common for using LIFT shackles to push the axle forward relative to the centerline of the fender from stock, and if buying a 3.5" lift leaf pack will move the axle slightly further back from where it is.

 

Yes, lengthening the shackle will cause the axle to travel in an arc. In this case away from the frame and towards the front with the front leaf spring mount at the pivot.

 

Rubicon express leaf springs are affordable and not a terrible ride. I'd kick those shackles out sooner rather than later and get with your plan for full lift springs. Also another note is that there are varying length front driveshafts out there for the XJ's. They are not all the same length so i wouldn't necessarily say just because its the same length as the front in your jeep currently that it would be the right shaft anyway.

A picture of what you've done soo far with your tcase output would be beneficial and in any case - installing the hack n tap yoke and then measuring the distance at ride height from center of yoke ear on the hack - center of yoke ear on the axle side is gonna be a key number in getting the right length driveshaft. Not uncommon to find a longer than needed front shaft and then have a driveshaft shop shorten it to your jeeps needs.