An obvious problem that can occur is for the timer motor to fail. The motors turn at 1 rpm, so it is quite easy to tell if it is turning.
A more common problem is for one or more of the drive gears to strip.
Removing the Tripper Arm screw, the Skipper Wheel screw and the three cover plate screws will gain you complete access to all components for careful examination.
It is easier to work on your timer housing if you remove it from the valve body. Pull out the timer retaining pin ( 5F ), slide power cord out of it's retaining slot, unscrew
Cam Shaft Bearing at rear of Cam Shaft, and then pull housing straight up.
Also the "OUT PUT CONNECTOR" # 21E ( 1031496 )> which attaches to and drives the Cam Shaft can crack or break.
On rare occasions the CAMSHAFT # 21F-3 ( 1031950 ) will break at one end.
Also, rare is a cracked SKIPPER WHEEL # 14F-6 ( 1031740 ).Close examination of both sides of the Skipper Wheel is required to detect this failure.
And last, but not least, you can have a gear post break in the housing body it's self. But only the back plates for the 440i version is available and not the "box" used with the older 440 version. It is simpler and prudent to replace the Complete Timer Assembly ( with the new 460TC ) at this point.
A complete replacement is also prudent if the unit is over 20 years old.
