Great post. I'll add a couple of corrections... the a340h most definitely was offered beginning in 1985. My truck has one and another 85 I looked at this week had one. There are several variations of the a340h, the early 22re models having drain/fill plugs in the rear most chain case for gear oil (while still having two trans pans that share ATF). The later a340h behind the 3.0 did not have this feature -- they were ATF all the way through.
Well I have one22re A340f  that I converted to 2RZ. Marlin told me had heard of 4 when I bought my duels adapter.

I have actually never seen an a340f behind a 22re, and have not found any proof that they exist besides lists like these of applications. Any pics of one?