I am a newcomer as of today. I was searching for exactly the question being dealt with here. I have a L3400. I had been driving it a few days managing the brush hog by gently using the clutch to engage the PTO and disengage. This was not very safe or practical long term so I got online and searched a few sites to be sure, then went out to investigate my PTO engage/disengage levers and cables. MAKE SURE YOUR ENGINE IS OFF. After removing a cover plate partially so I could access the lower PTO lever (I coulda been a contortionist in another life!), I was able to determine that if I moved the upper lever (right side near the seat), it just slightly moved the lower lever by means of the cable. NOTE: THIS IS HOW I LEARNED WHICH DIRECTION THE LOWER LEVER SHOULD MOVE WHEN OPERATING THE UPPER LEVER. Turns out the lower lever was seized just enough to only slightly shift and not travel through its full rotation. So I took the advise given on this conversation and lubed the upper lever area, the cable, the springs, and the lower lever area. I then cycled the levers back and forth in sync with one another a few times. From there, I only moved the upper lever, watching the lower one follow the upper one. PROBLEM SOLVED. Tested it by firing up the tractor and worked like a champ. Hope this helps some of you solve your problem. My guess is if you have a cable lever system like mine, this is by far the most common problem where the lower lever gets a bit sticky due to dust build up over time. I attached an image showing what I did.