Pulled the deck off my tractor to sharpen the blades. While the deck was off, I cleaned the shafts, regreased the bearings, cleaned the shafts, seals, etc. then greased the assemblies with the blade nuts loose. I then tightened the nuts on the shafts with my impact wrench. I greased the zirks one more time to make sure the shafts were fulled lubed. After reinstalling the deck, it seems that when I engage the PTO it pulls more off the motor than it did before and almost seems to drop the RPM's slightly. I got to wondering if there is a specific torque (or range) for the spindle nuts and it over-torquing could create too much resistance in the shaft's spinning. Any ideas on this or is just running the nuts down with the impact wrench okay? Don't want to damage any thing...