Re: 39 Packard OD solenoid

Posted by HH56 On 2022/3/24 13:55:05

I don't know which manual you are referring to but it sounds like it may be describing the later R9 or R11 OD circuits which do use the solenoid to engage OD. On those units the solenoid is engaged and held engaged to extend the plunger and hold the pawl in the sun gear the entire time the car is in OD. A large spring is used to retract the plunger and pawl after solenoid is turned off when kickdown is needed.

On the 39 only R6, the operation is just the opposite. The R6 solenoid is typically on only for a period of a minute or two and is used exclusively to retract the plunger and pull the pawl out of the sun gear for kickdown or whatever. As soon as that function is over the solenoid is disengaged and springs take over placing the pawl in position to go back in the sun gear.

Except for the R6 solenoid retracting and the R9 and R11s extending the plunger, the basic solenoid electrical operation is identical. Both pull in and hold coils are energized at the same time and both are used to do the job of overcoming inertia and springs to initially move the plunger. As the plunger moves and nears the end of the plunger travel, there is not a lot of moving effort needed anymore so internal contacts open to disconnect the pull in coil to reduce heat and amperage draw which leaves only the hold coil energized to keep the plunger in position. On all three models of solenoids the hold coil is energized anytime the solenoid is on. With the R6 and R11 solenoids only one wire is used to power both coils. The other end of the coils on all solenoids get ground by connecting to the case. The 40-48 R9 solenoid is different and does have a separate wire to power the hold coil but the overall R9 electrical circuit is much more complex and not applicable to your unit.