Solenoids

Since the solenoid valves perform all control functions, these valves must be durable and tolerant of dirt particles. For that reason hardened-steel poppet and ball valves are used. These are free from any close operating clearances, and the solenoids operate the valves directly. Direct operation means that these units must have very high output. They must close against the sizeable flow areas and high line pressures. Fast response is also required to meet the control requirements.

Two of the solenoids are normally-venting and two are normally-applying; this was done to provide a default mode of operation. With no electrical power, the transmission provides 2nd gear in OD, 3, or L shift lever positions. All other shift lever positions will function normally. The choice of 2nd gear was made to provide adequate performance while still accommodating highway speeds.