When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
On my BW1345, the linkage isn't really adjustable that I recall. You might crawl under there
and see if your linkage is just plum worn out and the holes have been made into ovals (for
example) but I for some reason doubt the linkage has anything to do with it popping out of
gear.
If you have a body lift, make sure the lever is not hitting the floorboard, it has been known to happen. Also make sure the motor mounts and the rear tranny mount are good and not broken. When I did my tranny swap in my 89, the rear mount was completely broken away, and the tranny/transfer case were just sitting there, gravity holding them in place. It's hard to tell this unless you put a pry bar under it and lift it.