Basically you got the gist of it all.

Rear output flange, CHECK

transfercase output flange is 30 spline, CHECK

The above linked marlin crawler 4 pattern flange is what you need to cure your issue, CHECK

Tomorrow I can check out the 'covers' and see what the bolt pattern is to help narrow down whats what.

I wasnt born with this knowledge nor terminology this is pretty much me learning about it all as I go. So please excuse murky explanations.

 

oh, and thanks for the input and help.

 

Put the d/s up to the output flange, rotate 1/8 of a turn, clamp it and drill 4 new holes.
Save $$ on ordering parts etc...


Edit-just saw scuba suggested the same thing...

 

Boy did this thread blow up after I answered and went to bed. lol. So my first answer is right? I was confused after the first few replies. Glad I went to bed. hahaha.

Now I got to go out and double check my backup driveshaft and make sure the bolt pattern is right, because it came off of a newer model. I was more worried about the length and not the bolt pattern. Pretty sure the length is right but I've had that thing almost a year and haven't had to use it. I guess my u-joints are better then I thought they were. lol.

 

I thought about the drilling option as well but in the back of my mind I just thought that if it was a hair off it could throw off the centrifugal force and cause a terrible vibration. So my buddy is just gonna hit it with his purse and get the MC multi pattern flange and call it good.

Sorry for the confusion initially, it was a long day, a lot of jumbled thought and I'm still learning terminology etc (not to mention mechanical info!)

His rig should be all bolted up and back together by the end of the week so updates should be soon!

 

Lol you won't throw it out of balance at all. If you drill each hole with the flange mounted to it, and drill straight through, you won't have any problems at all.
The 4 other holes won't matter because the flange will stay balanced due to the fact that the 4 holes on the outside are constant, and not changing their location or size.