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Chad, Technician
Category: Heavy Equipment
Satisfied Customers: 125
Experience:  17 years experience lead equipment technician and troubleshooter Mining equipment expert
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I have installed a FA series Muncie PTO onto my 2001 F550 7.3L

Customer Question

I have installed a FA series Muncie PTO onto my 2001 F550 7.3L diesel with a 4R100 automatic transmission. The truck was purchased with the "transmission PTO provision" and Auxiliary idel control module from the factory. This is my problem... With the truck in park,engine running,barking brake set, I engage the PTO with the APCM, the engine idles up, PTO indicator light comes on but I am not getting the necessary 120-130 psi out of the main transmission pressure port for PTO clutch engagment thus no hyd pressure to run the Auto Crane 6006H on the truck. I have taken this problem to three hyd shops, one transmission shop and two Ford dealers, one of which re-flashed the PCM the other ran an over lay wire from the PTO activation stwich to PIN 66 in the PCM. One thing that does not seem correct to me is that when I engage the PTO the Transmission Control Indicator lamp goes out. Can you Please Help? Dave M.
Submitted: 7 years ago.
Category: Heavy Equipment
Expert:  Chad replied 7 years ago.

Hi my name is Chad. I'm going to try to help you with this.


When you say the engine idles up, what are the RPM the engine is idling at.



Customer: replied 7 years ago.


Using the auxiliary idle control module (APCM) to engage the PTO, I have linked the PTO with the RPM control. I have set the lower limit @1000 RPM and upper limit @2000 RPM. Also we are getting power at the 12V PTO solenoid when engaged.

Thanks, Dave

Expert:  Chad replied 7 years ago.

OK that might be your problem. You have to have a minimum of 1200 RPM to get the needed 120 psi to activate the clutch.


Also were did they tap the transmission at?



Customer: replied 7 years ago.
When the engine idles up it is set to run at 1700 rpm. Also the hydrolic shop used the main pressure port behind the PTO pump. This has been confirmed by the second hyd shop and the transmission shop....
Expert:  Chad replied 7 years ago.
Did the shops checked the pressure with a gauge with out the pto hooked up, or did the just put a gauge in line? Reason I ask is to make sure there is not any problems with the PTO itself.
Expert:  Chad replied 7 years ago.

I'm not sure if you have these put these are Fords Manuals for the PTO and Troubleshooting


Also Something else I can across, but I doubt it applies to you.



"The PTO Circuit is wired properly but will not respond". When the vehicle battery is disconnected for extended period the powertrain control strategy "forgets" PTO logic and will not respond to commands for elevated idle until it has had a chance to re-count the number of teeth on the gear-set in the 4R100 automatic transmission (36-teeth for non-PTO 4R100 and 115 teeth for the PTO-4R100). To remedy this simply drive the vehicle a short distance. Typically less than a mile will be sufficient to prepare the strategy to respond properly. Driving in first gear will speed this up. Driving stationary with the rear wheels off of the ground will not work. Also note that once the ignition is turned ON, CRANK, and START, sitting and idling for too long before driving may bypass the strategy's "search" cycle, leaving the driving remedy ineffective. If this occurs, shut off the engine and start the cycle over. No need to rush to drive, but avoid unnecessary delay.


I'm still digging for info.

Customer: replied 7 years ago.

Sorry for the delay in response (I have a 7 yr old with homework questions...)

Pressure has been checked before the PTO solenoid. The transmission is just not responding to the signal to increase pressure. The coast clutch has been checked and it is engaging, the transmission shop even replaced it's solenoid with no improvement. Do you have any thoughts as to why the transmission control indicator lamp (the overdrive light on the gear shift arm) goes out when the PTO is engaged? This lamp should come on instead. I " think " this is the problem.

Expert:  Chad replied 7 years ago.

Are you talking about the overdrive cancel light?



"Cannot find the PTO Circuit". The Super Duty F-Series PTO Circuit wiring changed soon after 1/1998 Job #1. The PTO Circuit wires moved more toward the driver's side, under the steering column and onto the harness for the black 4-pin APCM connector. The wires shown as 18-gage are 20-gage. Job #1 began with Circuit 640, red with yellow trace, 18-gage (really 20-gage), then changed to Circuit 295, light blue with pink trace, 20-gage. PTO Circuit 322, correctly remains light blue with yellow trace, but there is another wire with the same color near it (Circuit 323, not related to PTO). To verify that the correct wire is chosen, check to confirm that the 4R100 overdrive-cancel light is illuminated as it normally should be when the PTO Circuit is activated.


You should not be able to engage overdrive with the pto on. If you can then you have a wiring issue


Expert:  Chad replied 7 years ago.

I have read the PTO manual 3 times now. Best I can fiqure is that the port is tapped at the wrong place (see below for where it should be) or your wiring is wrong.




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Customer: replied 7 years ago.

Thank you! You have given me something to work with. I just went out and ran the truck with the overdrive cancel light activated (lamp on) I engaged the PTO. The lamp went off (as it has been doing) but then I pushed the button and the lamp came back on.

I now need to check circuit 322 and 323 to confirm correct wiring. This may take a day or two since the hyd shop that did the install is in Reno and I live 30 miles from Reno. I would like to pay you for your help and stay in touch if future assistance is needed.

Expert:  Chad replied 7 years ago.
Let me know what you find so if I run across this again