Ford 5610 4WD problem

[Glennmackenzie]

Hi all,
My Ford 5610 has started engaging and disengaging 4wd by itself, noticeable when travelling on the road due to the load whining noise, then randomly it will pop out of 4wd (with an audiable bang) then it will be fine for a while then it will go back into 4wd and then pop out again etc etc. I rigged up a light to the sender wire to see if it was getting intermittent power to the solenoid but the light stayed on when switch was in 2wd but the problem remains the same so I am assuming the wiring is good. Does anyone have any other ideas?
Thanks!
Glenn

 

[wore out]

Hi all,
My Ford 5610 has started engaging and disengaging 4wd by itself, noticeable when travelling on the road due to the load whining noise, then randomly it will pop out of 4wd (with an audiable bang) then it will be fine for a while then it will go back into 4wd and then pop out again etc etc. I rigged up a light to the sender wire to see if it was getting intermittent power to the solenoid but the light stayed on when switch was in 2wd but the problem remains the same so I am assuming the wiring is good. Does anyone have any other ideas?
Thanks!
Glenn

You must be calling the solenoid "the sender"?

If so, it takes GROUND as well as power to keep the solenoid engaged. I don't know if it has a separate ground wire or grounds through it's mounting.

If you are able to measure the CURRENT to the solenoid and note if that changes, or not, when the FWA engages by itself that would be helpful. A sudden drop in current MIGHT indicate a "bad" ground or a failing solenoid coil.

If that remains constant there could be an oil pressure problem, would need to consult a shop manual to learn if there's a pressure test port and what the pressure should be.