Created with Sketch. Created with Sketch.
Getting Familiar with a Borg Warner R-10 R-11  Overdrive - Classic Car

Getting Familiar with a Borg Warner R-10 R-11 Overdrive - Classic Car

Posted by Jay Johnson on Jan 13th 2022

Every classic car enthusiast has one feature they appreciate most on classic vehicles and miss on modern cars. Maybe it is the nostalgia or squeezing all together in the front bench seat, the affordable power of the Flathead V-8, or the thrill of switching into overdrive as you get up to speed on the highway.

The Borg Warner Overdrive was one of the most popular add-ons for vehicles between the 1930s and 60s. Over 4 million vehicles came from the manufacturer with a Borg Warner Overdrive installed and many drivers added on aftermarket overdrives which were readily and affordably available, in some cases, for as little as in some years for as little as $20.

The Borg Warner Overdrive first debuted in 1934 on the Chrysler Airflow and DeSoto Airflow. The purpose was to improve gas mileage by decreasing RPMs at highway speed, made possible by providing extra gears beyond the standard three speed transmission of the time.

From their initial rise in popularity to their downfall in the 1960s original Borg Warner Overdrives are a fantastic feature for any vintage car. Whether you are lucky enough to own a car with one installed or dream of adding such a car to your garage, here are the basics on the Borg Warner Overdrive

History of the Borg Warner Overdrive

The Borg Warner Corporation, which formed via a merger of two long standing companies 1928, already had a background in gear and transmission manufacturing, but it was their joining of an overdrive unit to a standard three speed manual transmission to create the innovative Borg Warner Overdrive that they are most known for.

The initial purpose of the overdrive was to reduce engine RPMs for vehicles on the highway. High RPMs were becoming a significant challenge for cars as highway speeds increased with the advent of more powerful engines. Maintaining these speeds in third gear resulted in inefficient fuel mileage and a noisy ride.

An overdrive works by using a planetary gear to produce more evolutions in the wheels than the engine, hence the name “overdrive.” The Borg Warner Overdrive specifically could reduce RPMs by as much as 33 percent at speeds over 30 miles per hour.

Borg Warner had several different overdrive options available, but the two used in automotive were the R10 and R11. The R10 was the most popular, used in the majority of cars. It had three pinion gears in the planetary gear system and a ratio of .70 to 1. The bigger R11 was used for heavy duty automobiles, such as vintage trucks and in bigger cars like Packard and Lincoln models. It had four pinion gears and a .72 to 1 ratio. Your specific model will be clearly labeled near the solenoid.

The original overdrive was mechanical, and upgraded to an electro-mechanical component in 1939. In the later half of the 1940s, another upgrade engaged overdrive by holding the sun gear stationary in the planetary gear system. This final design would stay constant until overdrives were phased out.

The Chrysler Airflow, and its twin the DeSoto Airflow, were the first two cars to have a Borg Warner Overdrive installed in 1934. The vehicles were largely unsuccessful, but the overdrive quickly caught on.

Some of the factors that influenced Borg Warner popularity with customers included:

  • Better Gas Mileage - With World War II gas rationing occurring in the early 1940, any car that could run on less fuel was both patriotic and easier to drive. Traveling salesmen were also huge proponents of the overdrive since many had to pay for their own gas and this was a great way to save on those costs.
  • Better Driving at Higher Speeds - Highway building expanded rapidly throughout the 1920s and by the 1930s, early planning was already taking place for what would later become the interstate system. All of these highways now meant that drivers could travel safely at higher speeds, and they had the more powerful engines and cars they needed to do so.
  • Smoother Handling and Quieter Driving - The Borg Warner Overdrive was perfect for everything from our roadsters to family cars, and made driving around town or on freeways more comfortable.
  • Easy to Use - Switching into and out of overdrive was simple to do and nearly automatic on later iterations of the technology. Arguably, it is easier to drive than the standard stick shift with a clutch. Since most of the parts did not take a lot of wear, it was also relatively simple to maintain.
  • Affordable - As an option, the cost of a factory installed Borg Warner Overdrive was easy to justify for most car buyers. For instance, Studebaker offered theirs at $30 in 1950. For the improved driving experience, it often made sense to include this add-on.

The Borg Warner Overdrive started to see a decline in the 1960s due to the increasing use of automatic transmissions. It was used on fewer and fewer cars, with Ford as the last to include it in the 1967 lineup. The final automobile to come with a Borg Warner Overdrive was the 1972 Ford truck before they too dropped the overdrive for the following model year.

Between 1934 and these last cars in the 1960s and 70s, 22 different car models came with the overdrive, either standard or as an option, from companies that included:

  • Studebaker
  • Chevrolet
  • Ford
  • Hudson
  • Lincoln
  • Mercury
  • Packard
  • Nash
  • GM
  • Willys Overland

While the overdrive may not have immediately catapulted classic cars to top speeds - that reputation is largely the result of rock songs and movies - it does enable many vintage autos to safely drive on modern highways today and keep up with traffic while also making for a more comfortable ride.

Driving a Car with a BW Overdrive

Since overdrive transmissions largely went out of use in the 1960s, many people have not driven a car with a BW overdrive in it for a few years, especially if this is your first vintage car. For younger classic car hobbyists, this may even be your first chance to drive a vehicle with an overdrive transmission.

It is a slightly different experience than an automatic or standard stick shift, so there is going to be a slight learning curve. But once you get the hang of it, most people enjoy the smooth ride and high speed highway capabilities that a classic car with an overdrive provides.

This is a brief overview on how to work a Borg Warner overdrive:

  • Generally the overdrive control on the dash remains pushed in to enable overdrive.
  • When your car hits between 23 and 32 miles per hour, depending on the vehicle, let your foot completely off the gas and you will engage the overdrive.
  • Press the gas pedal to the floor and you will trigger the kickdown-switch, moving the car from overdrive back into third gear.
  • If speed drops below 23 to 32 miles per hour, the overdrive will disengage, putting you back in second gear.

You can use overdrive when driving around town, at which point it will function similar to an automatic car. As your speed changes, overdrive will engage and disengage.

On the freeway, overdrive will be engaged as you are traveling at normal speed. When you need to go up a hill or pass another car, you will floor the gas to momentarily disengage, and then let your foot back off throttle once you have reached the top of the hill or passed the car.

These are the basics to the BW overdrive transmission. We also have some great resources that go further into depth on driving a car with a Borg Warner Overdrive installed, as well as some common issues to watch out for - such as cars rolling away when parked if overdrive is engaged. Check out our Borg Warner Overdrive Report for the R10 and R11 overdrives, which can provide additional guidance on driving and getting the most out of your overdrive.

Many original BorgWarner overdrives in classic cars still function well today, although some maintenance may be needed to keep your overdrive performing its best, such as upgrading or replacing worn out parts. Additionally, classic car owners who are converting their vehicle from 6 volt to 12 volt power will also need to install a new relay and solenoid on the overdrive to avoid burning out any components.

Vintage Auto Garage has all of the vintage car parts you need to maintain your Borg Warner Overdrive with relays, solenoid, kick down switches, and even replica pull cables. Our Borg Warner Overdrive parts are available individually and in convenient kits to keep your classic car driving well around town and on the freeway. Look through our inventory and read through our specific resources for Borg Warner overdrives. If you have additional questions about which parts fit your vehicle and overdrive model, give our team a call.

read more