Overdrive front/rear shift difference

I realize this will be obvious to many, but hey, we have to start learning somewhere...

I'm wanting to get an overdrive from Herm, and already know I need a "rear shift" for the 29T x 6 spline. But what is a rear shift? Does that mean you throw the lever towards the rear of the jeep to engage OD?

Thanks in "advance" (Pun intended)

 

Just means the OD shift linkage exits the OD to the rear. This is the most common linkage you will find.

 

I've had a couple different front shift units but they don't work with the large hole transfer cases. The earlier cases have an indent? (for lack of a better term) on the case itself where the shift rail can fit into that isn't there on the later ones. Early cases can use both, big hole cases can only use rear shift. My diesel six has a front shift Dual matic in it currently.

 

Perfect clarification guys. Thank you.

 

You can also view the exact same / recent topic over here:
http://www.thecj2apage.com/forums/od-question_topic33086.html

 

Front vs. rear shift OD housings
Sorry for the fuzzy pic, but you get the idea.

 

Awesome info. THANKS