I have a JD 6400 with PTO problems Seems to work good in…

As a general rule the PTO clutch is not a big issue in terms of slippage. What we do see more frequently is the splines stripping out where the shaft goes in. I'm sure however that you have had ample opportunity to look at this in detail based on what you have already replaced. Most of the time the problem is electrical. There is a cheat that we use to rule out the electric portion of the circuit. You can use the differential lock solenoid harness and plug it into the PTO solenoid. Simply depress the differential lock to engage the PTO and tap a brake to disengage. The differential lock solenoid is located just above the PTO solenoid under the rockshaft. The harness should just barely be long enough to plug in. If the PTO works normally with no loss of speed or disengagement then the fault is most likely the PTO time delay relay (yellow relay located under the rear of the right side console).

Let me know what you are seeing and I will gladly assist you with further diagnostics as needed.

Thanks,

Kevin

If you are still getting slippage with the solenoid powered directly then the problem is most defiantly internal. While you can check PTO pressure it is unlikely that the problem is due to a pressure fault. If you would like to test PTO pressure use the following steps.

1. Operate the tractor until the hydraulic oil is above 120 degrees F.
2. Install a 500 psi gauge on the PTO pressure test port on the back of the tractor.
3. Set engine rpm's to 1,000 rpm and engage the PTO, pressure should be approximately 175 psi

If the pressure tests good the the there are no leaks in the PTO engage circuit and the problem is most likely in the clutch itself. Most of the time the torque load in 540 will make clutch problems show up sooner then they would when operating at 1,000 rpm.

If the pressure is low please let me know and I will gladly assist you with further diagnostics as needed.

Thanks,

Kevin

Ok, so the clutch looked good, all splines and drives look good and the clutch pressure is within spec. When you operate the tractor with the PTO in 1,000 there are no problems at all but when put in 540 the clutch slips under load. We have bypassed the PTO electrical circuit by using the diff lock harness and still the PTO slips. We are running out of the normal failures. In most cases we only see clutch or drive line failures on high hour PTO application units. When failure does occur it is typically just a new set of clutch discs, PTO brake, and seals and they are good to go again. What we have seen is the roll pin in the shift collar fail causing poor engagement in either 540 or 1,000. Most of the time it is the 540 that suffers. As the button wears down and wears into the PTO shaft itself engagement slowly becomes less and less. Make sure that you install a new roll pin in the #21 position prior to reassembly.

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Keep me posted,

Thanks,

Kevin