Power To The Front Wheels But Not The Rear

This is gonna be a big help when I get back. Thank you.

Hoping that's the only thing I'll have to order. This issue is looking like it'll be the most expensive fix so far if there's something really wrong with the t-case.

 

I'm gonna go ahead and knock on wood. Hoping that won't be the case.

 

Welcome to the world of old Jeeps. I have had to rebuild or replace the transmission and transfer case in all but one old Jeep I have owned. Of course I don't usually buy "nice" Jeeps.

 

Yes, the later F134 CJs had the single stick as original. The transfer case shift pattern has 4 positions; 2WD/Hi range (shifter all the way forward toward firewall), 4WD/hi range (one detent back from 2wd/hi), Neutral (two detents back from 2wd/hi), and finally, 4WD\low range (all the way back, three detents back from 2wd/hi)..
There is an interlock pill in the front bearing cap, between the two shift rails, that allows the shifter to correctly engage these 4 positions. If this interlock was left out, you won't get the selected combinations intended. This could explain somehow getting only the front driveshaft engagement. When shifting your transfer case, is the center bellcrank link (your photo in post #11) moving both shift rails in or out as you select different positions? Each position should be a different combination of shaft positions.
The D18 front driveshaft output shaft is driven by a sliding collar on the rear driveshaft output shaft. I see no way to have only the front driveshaft engaged without the rear driveshaft also engaged.
Edit: Looking at your avatar, it looks like you have a significant body lift off the chassis. A body lift can really mess with both clutch/brake pedal and shifter movement and geometry. as well as steering. Are you sure this is not the cause of your issues?
-Donny

 

Keys5a said "The D18 front driveshaft output shaft is driven by a sliding collar on the rear driveshaft output shaft. I see no way to have only the front driveshaft engaged without the rear driveshaft also engaged."

This is what I was thinking too. I don't understand how you could possibly have power to the front without power to the rear, regardless of how the shifter is working, or not working.

 

The only way I can think of for that to happen is the rear output shaft breaks behind the sliding gear splines. That is something I've never observed. One would expect a lot of slop at the rear companion flange/yoke if that happened.

 

Are we sure the rear differential/axle doesn't have something sheared, and the rear driveshft is actually turning?
-Donny