Mine started to leak on an 02 model also around 60k miles.
I took it to the dealer and they replaced the o-rings and had me going for about $130.00. I have learned since that it is a pretty easy fix and of course the o-rings are cheap.
Go to
www.thedieselstop.com and you should find all the information you need.
But to answer your question to have that happen three times in 109k miles is too frequent. I have heard of dealers ripping folks off charging for a new pump with all you need is o-rings.
Hopefully you can find the cause and get better service.
Good luck