Your dad thought he was driving a deuce-and-a-half in the big war. Sent the shifter into overtravel, possibly broke a split pin forcing things.

I wrote an article on overhauling an R151 tranny, a kissing cousin to your R150 (nearly identical in fact). Its here.

DO NOT attempt to overhaul the tranny without the factory service manual. I have had several guys try it despite my warning in the article to not do so. The article is not intended to replace the very excellent FSM. Be forewarned: I won't help if you do...

Gee, grumpy, ain't I? <img src="/forums/images/graemlins/drunk.gif" alt="" />

edit: [MANDATORY TACO CONTENT] Uh, the trannies are virtually the same in the taco 5 speed too...