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

Packard Don wrote:
Without the overdrive connected but with the rear end ratio that the overdrive Packard used, you probably would not want to drive much beyond 50 mph.

HH56 wrote:
What would be interesting would be if someone with both solenoids at hand could compare R9 and R11 solenoid plungers to see if any parts would interchange. I doubt they would but if that were a possibility it would open up some repair or conversion options. If an R11 repro that comes in 6 and 12v versions could also be compared to see if the r9 plunger could be swapped it would be even better.

Here are differences between solenoid plunger length as well as the bare R9 plunger assy with the ball on the end (ball is almost hidden at the end of plunger in the photo). If the repro solenoid plunger also had a similar travel and a screw on end cap that could remove so the inner shaft with the different lengths could be swapped it would open up lots of possibilities.

Note: I believe BDeB posted the R11 photo some years ago but am not sure if the photo shows the plunger extended or not. If not then it would extend around 1/2 inch to bring the extended measurement to about 1 1/2" so overall length of the R11 extended would be roughly 3/4" shorter than the R9.

Packard Don wrote:
One it’s enabled, it engages and disengages automatically, hence the wiring to the transmission and the governor. Also, there is a kick-down switch that knocks if off momentarily when the pedal is pressed to the floor for passing.

Ross wrote:
Since the OD is an add on at the back of the normal trans, if you leave the plunger in you will get the overdrive ratio applied to all of your forward gears. First will feel like second, second almost like high, and high will be .72.

A very expensive problem occurs if you try to back up with the OD engaged as the overrunning clutch will go to war with the shifter pawl and one of them will lose. There is an interlock inside the trans to prevent that but in well worn units someone can force it into reverse. When you go to back up chances are the engine will just stall.

Do you still have the overdrive relay hanging somewhere on your firewall? It looks like a voltage regulator but has 6 terminals. It is really not that hard to make the whole thing work and it is very cool, practical and enjoyable when it does.

Packard Don wrote:
Most of the overdrive electrical components are for 6v so to switch to 12v would require a custom solenoid (if such a thing is even possible) and a full rework of the relay's innards. I governor shouldn't care about the voltage but I'm not sure. You might be able to get by with some kind of voltage step-down device but it seems to me that it would be easier to keep it 6v, then use a step-up for any 12v items you may want to add.

Reproduction wiring harnesses are available and, as 6 requires a larger gauge wire than 12v, you could always do it stock now, then make the switchover later without having to make changes to the harness.

I'm just not sure I want to spend $2-$3k+ to try to rebuild the original 6 volt setup. I imagine a modern relay could take the place of the original one,