Front Drive Shaft Differences...

[onlyinajeep726]

Got a question for you guys about drive shaft, particularly the front ones.
 
When my MJ started life, it was a 2.5L with the AX4 and NP207.  It's now a 4.0L with AX15 with the NP242.
 
I have the original front DS from the 2.5L/AX4 setup which is awfully skinny for a drive shaft.  I also have the front DS from my XJ donor that had the 4.0L and AW4 with NP231.  I know there is no difference as far as the DS is concerned between the 231 and 242, but there is a difference between the AW4 and AX15.
 
The question I'm posing is, will the donor front DS work?  I'm pretty sure the skinny DS is far too short.  I've included pictures for comparison.





 

[Geonovast]

The AW-4 shaft will work for you if you lift the truck a bit.  With the AW-4 being ~1 inch longer than the AX-15, the front shaft is also ~1 inch longer, so you could bottom out the slip joint with it being too long.

[onlyinajeep726]

That's what worries me.  I am actually thinking about doing a 2" budget lift (coil spacers and chevy lowering shackles).  Going to save up for new shocks and those Monroe load levelers.  I suppose I can just wait and do all that at once.  You reckon 2" of lift would be enough to prevent bottoming out?  I really don't want to break the transfercase all to hell when I hit a pot hole lol.

[mvusse]

If you have access to a cherry picker or a fork lift you can slowly lift the driver side front wheel with the sway bar disconnected while watching the driveshaft.

[Timeless]

If the rig is put together, why not just measure the distance you have to work with?  You could also check front driveshaft clearance by using a a standard floor jack up front to at the very least gauge whether the rig will be street drivable.

[carnuck]

My general rule of thumb on the front driveshaft is that when your rig is sitting with the driveshaft level, you should still have 1" of compression left (so it can go shorter) to allow for the possibility of a bent control arm or other front end issues at a later date.

 

I use an engine hoist to lift the front of the truck and remove the coil springs so I can lower it back down and see how much clearance everything has.

[skidoo_j]

Just incase you decide you want to try and source a different length shaft from a jy rather than having one shortened.    http://www2.dana.com/pdf/J321-CV.PDF