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Modern truck transmission in a 1920s Packard?

Guest GLogan002

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Guest GLogan002

Looking at options to start touring my 1928 4-43. Has been a show car, time to drive more. Looking at three options: 1) high speed rear end (4.06); 2) overdrive, or 3) install a 5 speed Ford or Dodge truck transmission - a mechanic friend/restorer told me he saw and drove one in a Pierce Arrow a few years ago and it was really slick....syncromesh, 0.6:1 drive in 5th gear, and you couldn't tell by looking at it without crawling up under it. Does anyone have any experience in doing this exchange?

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I am surprised that no one has responded as many have been down this path. Notwithstanding my view that it is best to leave them alone, if you are intent on making a change and there is no denying that the car will cruise more easily if the gearing is increased, I would make the following comments.

Changing the rear end ratio to 4.06 : 1 will make a small improvement however an even taller ratio is better for effortless cruising but it will be at the expense of hill climbing and engine breaking down hill. Someone was supplying new ring gear and pinions with a ratio of about 3.5 : 1, years ago. I have ridden in cars with this ratio and it works very well but the cars die a little on steep climbs. This modification can be done without any external changes but significant internal modification is required to accommodate the larger pinion.

I have also ridden in a similar car to your 443 that was fitted with a Mitchell overdrive box combined with a low ratio rear end of about 4.7 : 1 . If you ignore authenticity this is a very satisfactory solution. It allows OD to be used on level roads to reduce engine strain and will climb and just about anything in top gear and crawl along in a parade at a walking pace. The modifications needed are a short jack shaft to the OD box and a shorter tail shaft to the rear end plus supports. It can all be removed and the car reverted to original.

Installation of a modern 5 speed gearbox with step up on 5th gear would no doubt work very well but I would think it would involve some serious and expensive modifications. I have not come across such a modification.

The Packards of the 1920's are all low geared and the engine gets very busy at anything more than about 50 mph. Going for a taller ratio will certainly improve this but I don't think it should be used for greater speed. If an emergency arises at speed, these cars will not respond well. The brakes are not good and do not always pull up straight, handling is poor with massive unsprung weight to through them off course. I doubt that these cars were meant to be driven fast, they were all about top gear performance everywhere.

My view is if you are not happy with your cars limitations then go for a later model that works to your satisfaction. Once the drive ratio is raised what then, synchro mesh gears, disc brakes, modern engine, fuel injection, radial tires etc. Driving a 1920's Packard is an experience and they are a bit slow on long trips but what's an extra hour or two each day?

Lets hear from others on this one, its a good topic.

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