PTO shaft spins slowly when PTO disengaged

   / PTO shaft spins slowly when PTO disengaged #1  

julichris

New member
Joined
Oct 7, 2004
Messages
23
Location
Lafayette Co., WI
Tractor
NH TC45DA, LS G3038
I have a TC45DA, 1400 hours. I have recently noticed that often when I first start the tractor the PTO shaft spins slowly when the engine is at low RPMS and no implement is attached. If I raise the throttle and increase RPMS, the spinning stops, or if I attach an implement to the PTO the spinning stops. I have never noticed this happening when the tractor has been running for a while.

I have searched previous posts and could not find any mention of this. Any ideas? Is this something I should be worried about.

Thank you.
 
   / PTO shaft spins slowly when PTO disengaged #2  
I don't believe you should have any concern. It's just cold fluid turning the shaft because the fluid between the plates in the clutch pack is bridging the gap between the plates and causing it to turn.

Multiplate clutches have very little gap between the plates when not engaged. The oil when viscous, fills that gap and causes freewheeling of the pack. Any load on the pack causes the pack to quit turning.

Some motorcycles with wet clutches do the same thing. Start the bike cold and put it in gear and it lurches because the fluid is causing the pack to turn.

My Kubota's do the same thing. I've never given it a thought or concern.
 
   / PTO shaft spins slowly when PTO disengaged #3  
As 5030 said, it's not a concern at this point, but it does indicate wear of the PTO brake, and it will get worse over time. The PTO clutch has a brake that is supposed to stop the PTO shaft when the lever is moved to disengage. This is a firm stop. With my rotary cutter spinning and the engine at idle, when I disengage the PTO on my tractor, the shaft stops turning in only 5 seconds. What you need to do to preserve your PTO brake is to always lower the engine's RPM to idle before disengaging a rotary cutter. Start at low RPM also and engage the lever slowly. Don't rev the engine to 1500 and just push the lever forward. That will cause extreme wear. My tractor has over 1700 hours and many of those hours are with the PTO running. My PTO works like the day I bought the tractor because I take care when engaging/disengaging. It does make a difference.

I would not worry about your PTO for now, but be prepared to have to do a repair at some time in the future. Take it easy when engaging and disengaging and that repair may be many hours away.
 
   / PTO shaft spins slowly when PTO disengaged
  • Thread Starter
#4  
Thank you both for your help. We use a flail mower quite often, along with rototiller, cone spreader, and rotary mower. The flail mower must put tremendous strain on the PTO brake because of the centrifugal force. We have always engaged the PTO at low RPMS but have not always disengaged at low RPMS - will certainly do so in the future!
 
   / PTO shaft spins slowly when PTO disengaged #5  
Thank you both for your help. We use a flail mower quite often, along with rototiller, cone spreader, and rotary mower. The flail mower must put tremendous strain on the PTO brake because of the centrifugal force. We have always engaged the PTO at low RPMS but have not always disengaged at low RPMS - will certainly do so in the future!

Actually, the rotary mower will put WAY more strain on that brake. It has much more rotational inertia.
 
 
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