Packard Forum Index » Pre-War (1899-1942)

Just a question for future reference is it possible to install overdrive on a non-overdrive 1940 transmission?

No, the transmission case is different for overdrive.

But, if you can get your hands on a transmission/ overdrive assembly, it CAN be installed in your car.

I did so on my 39 and worth every busted knuckle, dollar and minute to complete the job.

The R9 would be correct for the 40 models but that OD is somewhat complex electrically and mechanically and was prone to some issues. R9 trans-OD units do show up from time to time but some internal parts are harder to find and more expensive than for the R11 units. If you are not as concerned about 100% authenticity and can find a 22nd or 23rd series senior transmission with the R11 it would be an easier and more reliable installation. For installing in a 180 it needs to be a senior unit because the 356 engines had a larger input shaft on the trans and heavy duty OD gears.

Repro electrical parts are also available for the R11 units and even some aftermarket parts can be adapted whereas the R9 electrical parts are specific and as far as I know, not in repro. You will need to find all the R9 specific electrical items if you are starting with a non OD car.

Packard did make R11 kits available during 22nd series production for owners of 21st series cars and in one of the instructions it was mentioned older cars which had issues with the R9 might also benefit from the kit being installed. With that in mind there could be a case made that the R11 in a prewar car is not necessarily wrong. Without crawling under, the visible differences between the R9 and R11 would be the electrical relay and kickdown switch on the firewall.

So, I have a '40 Packard and an OD tranny from a donor parts car that my granddad had. I do not have any electrical components, only the actual transmission, and the overdrive unit.

Where would I begin on a control module? Would a 3.92 ring and pinion be appropriate on a car shipped to Denver CO designed for altitude?

Where do I identify the model on the OD/tranny?

Thanks for any assistance, I have had the same idea about converting a non OD '40 into an OD because I have the tranny and unit.

To identify the unit the R9 will have letters cast on the passenger side of the case. For a 180 unit or the heavy duty unit it will be something like R9-A1. For the light duty OD used in junior cars it will just say R9. The diameter of the transmission input shaft for the 356 engine is about 1 1/8" while the input shaft for the smaller unit is just shy of 1". The R9 solenoid and lockout lever will be located on the passenger side.

Not sure about the markings on the case for the R11 but the main difference is the solenoid and lockout lever will be on the drivers side. Transmission input shaft sizes I believe are the same as the R9 with the 356 engine needing a larger shaft.

For R9 electrical you will need the 6 terminal relay and 4 terminal solenoid which are R9 specific. To eliminate a potential problem in case of a shorted governor or wire you should also get the reverse safety switch and find or fabricate a bracket to add that to your car. Can't remember for sure but I believe the R9 signal light that indicates the OD is ready to engage is incorporated in the panel light switch in a 40 but I don't know if the switch is the same on a car without OD and if not, will it have the lamp socket.

For R11 electrical it is a 4 terminal relay with a fuse on the side of the case and a 2 terminal solenoid. Both are in reproduction although there has been a question if the stem length on the repro solenoid is long enough for the Packard adapter plate. Someone may have tried a repro solenoid and will have to answer that question. There is no signal light with the R11.

Common to both ODs are the lockout cable assy with the lockout switch located at the end of the under dash housing, the governor and a kickdown switch. R9 kickdown sw has 2 terminals, R11 has 4 and while it will look wrong, the R11 or an aftermarket switch will work for the R9 but not the other way around.

You can check with our vendors and keep an eye out on ebay for the R9 items but they are starting to get expensive and harder to find. Flackmaster would be a good place to start. There are a couple of OD specific vendors who have parts for all mfgs that used the B-W ODs that may have some stuff too. You can get a loom made at any of the repro wire harness places but since the car does not have OD now the wires that normally would be part of the main loom are going to have to be handled as extra wires incorporated in a special repro OD loom.