No adjusters on the rear brakes? That doesn't seem quite right... Your rear brakes to about 30% of your braking.... if they aren't working, that is something you should notice. (more effort required to get the truck to stop.) Of course, if you have rear disk brakes, with separate parking brake in the hat, all bets are off.

 

If you were addressing me......the DIH doesn't get an auto adjuster -- there'd be no way for it to ever auto adjust, at least not the typical way of backing up and stomping the pedal.

It definitely has an adjuster and it's just a star wheel held captive by a spring that rests in the "saddle" of the "star teeth" (so, very similar to any standard drum) but no clicky-clicky arm ....

.....all of which, of course, resides next to the thingie, near the kanooter valve and aligns with the muffler bearings....as long as I'm using the technical terminology

 

This is the extent of the DIH adjuster, basically a turnbuckle and a spring