Packard Forum Index » Post-War (1946-54)

How does one definitively determine if you have a R-9 or R-11 overdrive?

This is my dad's car and the solenoid is located on the passenger side and it also has the hand operated overdrive engagement lever on the passenger side. The governor is on the drivers side.

THANKS for the help!!!

Disregard...found it cast on the passenger (right) rear of the OD unit.

It is a R-9.

Is there anything better or worse about the R-9 verses the R-11?

If the R-9 is bad (my dad heard a loud clunk and then it no longer drives in OD forward. I does drive in normal forward and reverse)?

THANKS,

Bill

R11 is different mechanically and simpler electrically.

The R9 had an issue that if for whatever reason the solenoid stayed engaged and unit failed to drop out of OD when slowing and stopping and the car was then shifted into reverse the OD could lock up. If the driver applied significant power when trying to make the car start moving in reverse while locked, the OD could be severely damaged. There was a stopgap electrical "safety switch" supplied which was installed to absolutely cut the power to OD and force solenoid to drop out when reverse was selected. It was somewhat successful but only a minimal solution because if something mechanical was causing the solenoid to stick the switch could not help. R11 revised the internal components so eliminated the mechanical reason the lockup happened.

After R11 introduction, there was a factory authorized R11 field install kit for owners that might have experienced the issue and wanted to buy the R11. A detailed description of the R9 problem, some reminders of the issue and info on the switch were written. Finally Instructions and components for the kit were listed and are all in various service counselor articles from the late 47 thru 49 period.

The R11 will fit with minimal changes to the car. Basically drill a couple of holes and relocate the lockout cable to driver side, replace the kickdown switch and relay and then revise the original wiring for the different electrics.