Properly sizing PTO shaft

[RoyJackson]

If you do rent an implement and the shaft is cut just a tad too long, you may be able to make it work by adjusting the top link. Also, many implements have multiple holes/pin points for the lower link connections. Checking all this "fit" out is very important as you can do significant damage to the implement, PTO shaft or worse, your tractor, with too long a PTO shaft installed!

Best practice is to hook up and carefully check the fitment through the full range of motion of the lift.

I don't think you want to hook it up and check...not before you measure...right?

 

[Baby Grand]

The PTO shaft must be short enough to still have travel so it will not bottom out in the shortest position it will be in. This is normally when the PTO shaft is level. Mount the implement, but don't hook up the PTO shaft, raise until the shaft would be level, then see if the PTO shaft will collapse enough to install.

Zebrafive has it right except for the level part. Different tractors have different lifting arcs at the three point hitch. Just look where the shaft would be the shortest point, if would you can't install or uninstall the pto shaft the its too long.
Don't take a chance with a long pto shaft!!! Been there done that, 10 k in damage to my tractor.

As yelbike says, if you can't install or uninstall the pto shaft, then it's too long.

Taking Zebrafive one step further - Not only does the PTO shaft need to be short enough to still have travel so it will not bottom out in the shortest position it will be in, it also needs to still have 3 or 4 inches of overlap between the two shaft halves when it's installed and fully extended.

So, not too long and not too short, but just right.