Years ago my father bought a rebuilt aircooled Vanagon trans from a fella who's project lost steam. 
So not from the rebuilder itself, but at a good discount. 

Forward to now and we put it into my van and while adjusting the linkage 
What a pain that is.. While I can get it nicely into all gears (after a buncha tiral/error and cursing) 
But no matter how I adjust the linkage at the pinch bolt coupler in the middle 
I can't get 1st to stop popping out.. 
It's frustrating laying under the van working with the linkage pinch bolt where it takes micro-mm adjustments to make from little to too much difference. 

I feel I need to lengthen the overall shifter length to keep 1st from popping out. But I can't move the balls/arm on the trans any more (rearward) when in 1st by the shifter.. 
So since it's all the way pushing back, maybe I need to shorten the arm to not engage 1st to the limit? That seems counter intuitive. 

Also I heard of at least one other incidence as mine where the poster was recommended from 2 trans shops that 1st gear would seat in after some time. And in fact did for this poster in about 2weeks.. 

Anyone have any tips or btdt tricks to getting the 1980-83 aircooled (diesel) linkage set up and happy?

I do (did) have new bushings in the shifter linkage in the past 3yrs. And the old transmission wasn't bad just getting tired from a lot of heavy use. 

Thanks

Dan in Syracuse