My coutershaft seal (#27) is leaking and I'm going to change it - should be a simple job but I noticed from the parts diagram that there is an O-ring (#26) in the mix - should I replace the O-ring too ? Could that be the cause of the leak ? I'll likely change it too (cheap) but was wondering why it's there.

Thanks, Eric

Diagram

 

Replace them both...mine liked to leak there...always after a dune trip...so I would just pull that spacer and wipe off the seal and it would work again...be carefull not to hurt the seal area...pull the old one with a seal puller or screw a small metal screw in to the seal grip it with pliers and pull it out

 

The O ring is what go's bad first time
mine went I replaced everything second
time just the O ring and it fixed it I got
a few O rings just so when it go's again
I don't have down time

 

The o-ring seals the area between the output shaft and the spacer (spacer slides over the o-ring), then the seal is between the spacer and case. So I would replace both.