A500 42RH
On the OD and lockup connector, the center wire is keyed ignition 12v.
If I remember the front wire is grounded to engage OD, and the rear wire is grounded to engage lockup.
(I may have that backwards) but that is easy to google.
Mine is set up using pressure switches to shift into OD and lockup completely automatically.
The switches are adjustable for desired speed of engagement.
For example, with the 4th switch on and 5th off, the trans shifts 1-2-3-OD.
With both switches off it shifts 1-2-3 like a 904.
The way things are adjusted currently, OD comes on at 50mph and lockup at 70 with both switches in the auto position.
The switches on the shifter activate a relay to ground the front and/or rear wires of the 3 wire connector.
As far as I know from your description the thing right above the cooling fitting is the front band adjustment.
On the OD and lockup connector, the center wire is keyed ignition 12v.
If I remember the front wire is grounded to engage OD, and the rear wire is grounded to engage lockup.
(I may have that backwards) but that is easy to google.
Mine is set up using pressure switches to shift into OD and lockup completely automatically.
The switches are adjustable for desired speed of engagement.
For example, with the 4th switch on and 5th off, the trans shifts 1-2-3-OD.
With both switches off it shifts 1-2-3 like a 904.
The way things are adjusted currently, OD comes on at 50mph and lockup at 70 with both switches in the auto position.
The switches on the shifter activate a relay to ground the front and/or rear wires of the 3 wire connector.
