Russ and others-
This is actually a common problem on the 48, 54 & especially the 60 inch decks on the 4x5 series.
If you imagine everything that rotates between the engine and ultimately the mower blades, the gear box on the deck itself becomes the weakest link in that path.
John Deere recommends that the PTO be engaged at full throttle. Because of this, the mower blades accelerate from zero to max RPM in just a millisecond when the PTO knob is pulled. Imagine the strain on the gearbox when three heavy, 22" long blades on a 60 deck have to be spun up immediately like that...
Time has shown that the gears in the gearbox aren't capable of handling the sudden shock and load when a 4x5 tractor is cranked up to full throttle before the PTO is engaged. This is especially true if the deck happens to be below a 455!
The Diesel in the 455 has enough torque to spin the deck up with the engine at idle. When I mow with my 455, I engage the PTO at idle, let the mower deck spin up and then accelerate the engine with the PTO engaged- MUCH easier on the gearbox! This also works with a 425 or 445 at only 1/4 to 1/3 throttle.
Mike
(Message edited by dlnw98 on August 07, 2014)