D-20 Lo and Hi front with interlocking pills

While I had the t-case apart installing the 3.15 gearing I decided to twin stick as well. The FSJ Pickups, Cherokees, and Wagons have a u-shape shifting pattern so their able to use the front and rear axles independently unlike the CJ D-20. An added benefit on the FSJ and Bronco D-20 is the slightly larger case so there is no need for grinding to install the larger 3.15 gears.

To gain independent use of the front axles I would need to remove the shift rail interlock pills or be lucky enough to have worn pills which I don’t. By removing the pills you stand the chance of binding and damaging the t-case by accidentally shifting the front in low and the rear in hi or vice-versa (the interlock pills keep that from happening).

If I was going to twin stick I wanted to use both axles independently but also wanted the safely of not binding the t-case especially when letting others wheel my Jeep. I decided to modify one of the shift rails enabling me to use the axles independently hi/low and still retain the pills.

There are two small recesses for the pills on the rear shift rail that I lengthened inward to match the one pill recess on the front shift rail.

I marked the rear shift rail where I removed some material.



I re-installed both rails in the shift housing with the interlocking pills but minus the detent springs and balls. I shifted the rails with no interference with the interlock pills and still had the safety benefit of the pills.

 

I like this. Not exactly sure what you did, but I want to do it.....

 

Once you have the rails out its very simple. If you look at the first pic the rail on the right has one recess on the right side for the two interlock pills. On the left rail there are two small recesses that need to be elongated inward as the markings indicate. I used a bench grinder then finished it off with a drumel. The measurement does not have to be precise.

Here is another pic to give you somewhat of an idea. I used a couple of fuses to simulate the interlock pills.
Note: when positioned correctly in the t-case the rails would be rotated down and the poppet spring and ball would be under the rails.



In the bore you will see the interlock pill and poppet ball.