Installing roll pin into shift fork in a 915.
 

Attempted to install the shift rod fork roll pin and failed miserably. I damaged the pin as I removed it-anyone know the exact size? Also, what's the trick to installing the roll pin so it seats in all the way?? So close to getting her back together!

I usually file down or mush it in the vise to get a little taper on one end. Start it with my thumb. Then whack away with an appropriate size drift.

I don't know the size of yours in question but just stick a few different size Allen keys in there until one is snug and I'd say you are there.

I used to have trouble with these too until I picked up a set of drifts on impulse at harbor freight. All of mine had some kind of character to them courtesy of the grinder for whatever I was needing the tools for at the time. This went on for the past 35 years with the same drifts. The new ones all have clean flat tips and a variety of sizes. Never had a roll pin problem since.