Linuxfarmer, we have about 2700 hrs. on the 1688 and my local dealer just told me to slide the coupler back and grease the splines, but when I did I saw that it should have been done 10 years ago. They said "Yeah you should grease those splines every winter". Thanks for telling me now, right. All you have to do is take the 3, 1/2"bolts out that hold the coupler to the motor side and you can work the coupler and pulley toward the hydro. Same procedure you use to change the belt. It isn't easy to get grease on the splines, probably need a bent screw driver or something to spread it on there, too small for your fingers. Sucks to have to pull that pump, but better in the winter than in a mud hole somewhere when I need to be harvesting.
We have a great local service department that makes owning a Axialflow even easier, this is not the only thing "you would have never known" that they have told me about. Thanks for all the info, guess I know what I'll be doing tomorrow.