Redrilling transmission tailhousing to lower clocking

[DirtyComanche]

My situation is I have a TJ transmission and it's mounted stupid high in the trans tunnel to try to keep the engine high.  This means I'm having a lot of trouble getting the transfercase I intended to use to fit, or for that matter the one I didn't intend to use (a bog standard NP231).  I was just going to cut the floor and make it work, but it seems I'm going to have trouble with seats if I do that.

 

Redrilling the tailhousing to the standard clocking is a common solution.

 

Has anyone seen any failures associated with doing so?  It's pretty Swiss-cheesed after you do this, assuming you don't weld up the old holes.

[OldSch88L]

I don't remember the exact number of degrees between a TJ and XJ pattern, but you end up with enough meat between the holes. I've been running a clocked TJ AX-5 for like 4 years with no problem so far.

[Pete M]

how much higher than stock is the trans?

[DirtyComanche]

1 hour ago, Pete M said:

how much higher than stock is the trans?

 

No idea.  Probably an inch or so.

[dante2]

I had to clock the transfer case down when I swapped out the 5spd to an AW4 in my YJ. I think it was about 10 degrees or so. Still had plenty of material between the holes. Been running this combo since 2016 with zero issues.

[schardein]

I run a Chevy 5.3/Jeep NV3550/Dana 300 in my 83 CJ7.  Currently, I use a clocking ring and different input gear in the transfer case (with deeper splines to account for the width of the ring), both from Novak, to get the nearly flat clocking I wanted.

 

But, when I initially put the transmission and transfer case together (in 2007, with a 4.0HO engine), I just re-drilled the transmission flange to use the transfer case at about the factory clocking.  It was rather tight, as not much "meat" was available on the flange.  But, it worked with no issues and I wheeled the Jeep hard until 2014, when I tore everything down for the 5.3 swap.

 

You should eyeball you flange and see how much material is available.  Look on the backside to make sure there are no stiffening ribs in the way.  Make a paper template of the original holes or use a gasket as a template if one is available.

[DirtyComanche]

I think I'll just drill it.  I can't find anyone that's had it fail.