Ford 545C Transmission Lockup Not Working

Hi again Ford Fans. I have a Ford 545C loader tractor I bought this last fall that has a transmission problem that I can't find source. It is the 3 cylinder diesel with an 8 speed electric solenoid shuttle shift with the torque converter lock up feature. the transmission works fine through all the gears in forward and reverse. It is smooth operation with no perceivable slippage but the lockup clutch in the torque converter will not function when the button on the end of the shuttle shifter is pressed. When the transmission is in any forward position and the green lockup light is illuminated nothing happens. I went so far as remove the loader to get at the lockup valve on the right side of the bell housing area. I removed the valve and bench tested it with 12 volts to the solenoid and it cycles great and when I applied air to the center port it directed the flow to the lower port when energized. To further check the electrical circuit I put a node light to the solenoid connector it will illuminate 3 to 5 seconds after the lockup dash light comes on so the modulator is working correctly. The coil in the solenoid has 8 ohms of resistance as per the service manual. After reinstalling the valve and changing the transmission oil and filter it still does not lock up. I have another one of these tractors that works fine. It is a 445D 4WD with the same transmission I used as a comparison. I started it and put it in 5th gear and placed the shuttle in forward position while holding the brakes at a little over idle where I could tell it was slipping through the converter. While holding the brakes I engage the lockup and when it engages it will almost instantly kill the engine just like dumping the clutch on a manual tractor at low engine speeds. That's the only way I know of testing it short of running it in a higher gear down the road and waiting for it to power shift into the lockup position. To cold right now to try that so when I apply my same test to the 545 it will start to pull in any forward position but nothing when the lockup position is selected even though the dash indicator comes on immediately when the button is pushed and I wait the five or so seconds for the solenoid to cycle. I've done as much testing as know and am reasonably sure the problem is not electrical or the lockup valve assembly. While I had the access cover off and the valve removed and reinstalled I can see the rear of the torque converter and it looks new or rebuilt but I have no way to tell as I don't know the tractor history. And after studying the service manual I could find no way to test the operation of the lockup hydraulic system or take any pressure readings other than on the shuttle valve. Can anyone out in Ford country advise me if there are any tests for the torque converter/lock up clutch short of spitting the tractor and taking it to a transmission rebuilder for service. One final thought, if the torque converter has been replaced is it possible to put in the wrong one from the 4x4 shuttle without the lockup clutch, Don't know if it will fit and work just no lockup even though it has the valve and oil passages.


This post was edited by kingslandkid on 02/06/2023 at 07:10 am.

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.