Your CD experiences with aftermarket gears matches mine. Actually, the Toy housing specs are so consistent that the prior pinion shim makes a very good starting point.
So, I took apart my ARB, and what did I find?
a) The thing grenaded, holding on only by a spit and a prayer.
b) It was jammed with crud due to the typical lack of maintenance of Red Chili.
c) There was a dead mouse in it, and as the corpse expanded it locked the diff.
d) Not a dang thing. It was a thing of beauty and a joy to behold.
If you picked d), "we have a winner". I changed the piston to upgrade to the new design, took everything apart and cleaned it up, and installed the new return springs that TR Burris sent me, just cuz. Oh, two other things: the backlash was .010", a couple thou more than I like, so that was good to fix. Also, the hard air line was brushing against the ring gear, a likely failure sometime in the next year or two (I did say 'lightly').
So what made the 'bang'? Well, when moving the truck out of the garage last night, much to my surprise I could not MOVE the ebrake lever. Turns out then dang cable is melting, in close proximity to the new 3.4 headpipe. Somewhat of a heat management issue methinks, hafta contact Mike Caskey on that little detail. When I finally forced it to set the brake, then release, it didn't. So I banged on the lever under the truck with a rubber hammer until it released, then realized: it probably hung up that day when it banged, and as the cable warmed up, it finally released fully, banging against the stop. *Maybe*, mystery solved.
Heb Dduw, heb ddim; Duw a digon
I'm that gun-totin', farm-raised, evangelical, pro-environment, OHV ridin'/drivin', Southern civil rights pro-labor Liberal yo' momma told you couldn't possibly exist.