The split pin came out of my drive shaft and cut a moon shaped hole in my tranny. Has anyone ever seen this before. 159 hrs and 403 miles only

 

Yep had that happen to my 2002 Sportsman 700..Pulled tanny and had it welded and replaced pin with a stainless bolt..No more problems..

 

Same thing here! Had a 700 brought in for making a grinding noise,spring pin had started to come out and was grinding against the transmission case. Put a bolt and nut on it also instead of a new pin(cut off the excess bolt and ground flat so even the nut wouldn't come off) because of customer's fear it would happen again. Didn't grind all the way into the gear case though. Caught it in time. OPT

 

check the u-joints on the rear drive shaft, a bad u-joint will cause the pin to work its way out, i replaced the roll pin with a grade 8 bolt and self locking nut

 

Same happened to me with my first 800 popo(05). Luckily, dealer replaced tranny under warranty and have never used another rollpin again! Used shearbolt/nut from a simplicity snowblower on front/rear shafts on every popo since with zero issues.