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

All, looking for opinions here. Background - I have a 1937 Packard 120, all stock. ~56,xxx miles, all original condition. The engine was refreshed a few years ago with an in-frame overhaul. Rear end ratio is 4.09:1. It will cruise effortlessly forever at 45-50 mph. I am happy driving it 55-60 mph for long periods as well, which it does without complaint or overheating. I've had the car to 70 mph a few times, and it is fine but certainly not sustainable, and it feels like I'm racing the engine. In a few years, I'll be moving to an area with lots of 45-55 mph country highways and no interstate.

The transmission leaks oil (I think from the cover on the input shaft, but cannot tell for sure), and the second gear synchro is worn. Shifts fine cold, but once warmed up, even with double clutching, it is sometimes very difficult to get it into second gear. It will be fine for the summer driving season, but as I'm thinking of post-Hershey winter projects, I have a decision to make. Option 1 is to simply rebuild what I have. I've rebuilt this same transmission (on a 115) before, so not concerned about the feasability, and I think parts should still be easy to come by. Option 2 is to find an R-11 overdrive, find a spare '37 transmission cover to modify the shift forks to work with the R-11 while retaining floor shift, and get a new driveline to modify.

I know I could modify my current driveline and transmission cover, but I want to be able to return everything to stock if I desire.

Does the frame need to be notched at the rear output of the transmission for this mod?

Given that I will likely rarely, if ever, see speeds over 60mph for the foreseeable future, is it worth the time/effort/energy/money to convert?

Again, looking for opinions here, so I'm interested in your thoughts, especially if you've done the conversion or driven a similar car. Thanks!

I would vote no, based on that info. I'm actually curious why you are weighing it as it sounds like significant extra money and work for little conceivable benefit.

Does "all stock" means mostly original condition? Engine and transmission are original to this car, etc.? In this case, just fix whatever you have. No need to "modify" a good original car.
How often are you planning to drive it, anyway? My usual cruising speed is 45; especially considering the lack of seat belts, I am taking it slow

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jw4 - yes, it is an all original car. Details are in my project blog in my signature line. I didn't want to go through the entire history.

I plan on driving it quite a bit. I've put ~2500 miles on is in the last four years, and I have visions of a few longer tours (i.e. Pacific Coast highway) in a few more years.

You could stay closer to original and avoid any frame modification by changing the rear axle ratio from 4.09 to around 3.75. I believe that new gear sets are available. Tire diameter should be 31". Some tires have less diameter, and that is to be avoided. Diameter over 31" will result in fender interference.

Just my two cents but OD is nice to have and if the budget allows, I would keep an eye out for a 48-50 junior transmission with R11 OD and pick it and any of the needed auxiliary items up particularly if you find them at a good price and even if you need to store things somewhere long term. With your assignments, maybe some family members would donate a few feet in their garage so you could have things shipped there and wouldn't need to try and cart things around. In 5 years or whenever you start your longer trips those items won't be any cheaper or I doubt in any less demand but you will have a better option if you have the parts..

If situations change or you decide not to go ahead with the project then you can always sell again and probably make a few bucks because you would hopefully have a more complete setup or maybe a full ready to install package by that time.

Another option if you want to have an OD but keep the car almost original is to remove the driveshaft and set it aside for reverting back to stock then install something like a Gear Vendors OD unit in its place. That unit could be supported by an easily removed structure bolted to the frame rails and would probably require little more than a few holes in the frame and new custom made sections of driveshaft in the way of mods to the car. An added bonus is you would not need to do anything to convert a newer transmission to a cane shift.

As I recall, several years ago one of those external OD units went into an early 30s model Packard. Some photos were posted here on this forum but may have been lost with the server upgrade. All the progress photos and details were on a private website which I don't believe is accessible anymore.

Overdrive is one of the best things they've ever come up with. I wish there was a unit that would bolt into the 35-36-37 cars with no frame mods and retain the floor shift. OD offers great in-town performance and excellent results on the open road, and you get a "passing gear". On a coupe or 2 door car, I don't think you'd need to change the 4.09 gears to the factory issued OD lower axle gears. It might be a good idea on one of the long wheelbase cars or for a lot of mountain country driving.

Okay, I just looked at the photos... I would not touch a nice car like that with any mods (even the ones that no one can see, because you'll know what you did ). An original car is only original once. Very easy to screw this one up, impossible to undo. All of them "modifiers" are always looking for an unrestored original, to do their dirty deeds with. While no one usually wants a modified vehicle, unless you did it yourself and can no longer sell it for the same reason.
Old cars are old cars, if you want one with overdrive, you can always get a newer model

I also have an overdrive in the cardan shaft. Best decision I've ever made. 2 liters less fuel consumption, 25 percent reduction in engine speed. The car is now really suitable for long journeys.

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Another option is to use a 53/54 senior rear end/axle. You would go from a 4.09 to a 3.54.

The track width and bolt pattern are the same. The swap just requires moving/changing the spring tabs on the axle. Speak to Flackmaster. He has done the swap before.

This is what I am eyeing for the Jackard.