Ford PTO clutch pack

I wrote a couple of weeks ago and got great advice on what was the cause of the PTO failure in my Ford 6700. of course the mechanic denied any involvement but i felt better knowing what really happened. We got the new (rebuilt) clutch pack installed and the PTO seemed to work fine until we began baling hay. I have a Claas round baler and the tractor worked until the baler started loading up and just before the bale was fully formed, the PTO quit turning. After dumping, the PTO turned again until put under a full load. Any PTO experts out there know what is going on? I mentioned I put in a rebuilt cltuch pack because I am concerned that might be part of the problem. Thanks to all. Kirk

Can you monitor the oil pressure to the clutch pack when the oil is cold and while working the tractor.... do you know what the pressure is supposed to be and how to connect up a gauge?

Get a gauge on it, then get it warmed up. It calls for 160-180 psi at a fast idle.
You connect the gauge on the bottom of the hydraulic pump. There ~should~ be a plug there, or a line for the dual power. If it has DP, 'T' into the line...
Go through all the functions with the PTO engaged/disengaged, DP high/low, FWD in/out (if it has FWD) and check the pressures in ALL combinations. When you find the leak, let us know.
It is possible that you have a leak on DP low that does not exist in high... and if were baling along until it got full, and then dropped back... you would then lose the PTO too.
Pressure gauge is the only way to start sorting this out.

Rod

While I am not near as smart as Rod on this, my 6700 will not turn the pto with much of a load at all with Dual Power in high. Asked a mechanic at a local dealer and he said that most would not, and he recomended not running the pto at all on the high side of DP. I have not done it since the first time I cut hay with it 7 years ago and it has run fine in the 1000 hours I have put one it.

Hope your problem is that simple.

Good luck.

Dave

I hope you haven't been using the DP in high for the last 7 years.... because you have a leak on the high side somewhere.
The only reason for the PTO to be affected by the DP is because of a leak at one of the DP clutches. I hope your mechanic has learned a little more since then...

Rod

Dave, I hate to sound so blasted ignorant but I have never worked on the PTO or ever had a problem with any. I've been operating tractors for 45 years but we have a cattle opeartion and it's pretty much get on and go. Hook up a baler, mower, box blade or rake and we've done about all we're going to do. Can you give me a little more explanation when you talk about the DP. I don't think the "dual power" is referring to the tranny but i'm not familiar with any other setting. Thanks, Kirk

On our bigger Fords, the Dual Power clutch pack, and the PTO engagement piston and PTO brake band piston are powered by a separate very small hydraulic pump which is piggy backed on the main hydraulic pump. I do not know if the 6600 is set up this way, but I suspect it is. That little hydraulic pump is a gear pump and is pressure reliefed at about 300 psi. When the engine is running, that pump is running. The body of that pump is a cast aluminum sandwich with hardened steel gears. Any grit which has gone through that pump will have scored the aluminum walls of the figure "8" opening the gears run in. So the pump is easily worn out and oil bypasses around the outside of the 2 gears losing pressure. My tractors have a brass tee with plug in the external steel line which goes forward to the Dual Power. You take the brass plug out and hook up a tranny pressure gauge with a hose on it, and make the pressure readings as described below. IIRC, these pressure checks can be done with the tractor tranny in Neutral and the parking brake engaged....engine running. Each slave piston has rubber "O" rings and it is possible one or more has failed, thus the loss of pressure in one function.

To the better experts, please correct any errors I may have made as it was about 15 years ago when I dealt with this issue on my Ford 9000.

Paul in MN

The only time I use it is on the road in 8th. Other than that I always leave it on the low side. I figured you were smarter than my mechanic you and others on the ford board have helped me alot more the last 4 years than the dealer ever did!!!

Thanks

Dave

My 6700 and every other 6700 I have looked at had dual power. There is a toggle switch type pedel between the clutch and breaks. You "roll" it forward it makes you go a little faster, backwards goes a little slower. It makes the 8 sp trans kinda a 16 sp. The way the dealer explained it to me and I am thinking it says in the book (could be very wrong, if I am some one will say) that the pto does not need to be use with the Dual Power set on high. Rod says if the pto doesn't pull a load in high there is a leak on the inside. He is more than likely right from past experiance with his post, I just know that I have good luck not use'n the high side very much at all and never use'n it and the pto at the same time. I am kinda like you, I am not going into a tractor for a problem that I can avoid by just going .5 mph slower. When going slow don't work, I will look further into it.

Dave

As I think about this some more, I think the oil being pumped but not being used by activating one of the pistons is then flowed into an internal oil passage to some of the tranny bearings. But this may not be true on the smaller tractors. Again IIRC, this is true for my 9000 and TW10, but not true for the 8000 as it has only splash lube in the tranny.

Did I understand that an explanation of the DP was wanted? The DP is a separate planetary gear 2 speed (low and normal) multiplate clutch activated tranny in the bell housing behind the main clutch and forward of the main tranny. It can be serviced by doing a normal clutch/tranny split and unbolted from the front of the tranny for rebuilding without taking the main tranny apart. (Eat your hearts out, you IH fellows with your troublesome TAs)( I have 2 IH tractors with TAs that have needed servicing...what a pain!!!) Well, that is the short course.

Paul in MN

There are some differences between the 4 and 6 cylinder tractors. The 4's run at a lower pressure... 160-180 is where they peak out, but as far as I know the supply side is the same. Pressure regulation is done in the PTO control valve.
Lube oil to the DP clutches IS different though. The 4's get their lube oil off the cooler return so the tractor is not dependant on being run in DP low for stationary PTO work like the 6's were.
Otherwise, as far as I know, they're quite similar.
I've never opened either one yet. I've been lucky enough to catch the pressure problems I've had early.... and haven't destroyed the DP... yet.

Rod