Here’s an interesting and useful feature designed for the muscle cars of the ’60s that unfortunately, was never adopted: the Dana two-speed rear axle, aka the Streep.
The Motor City’s muscle car era—1964-74, roughly speaking—was a lot of fun, but it wasn’t entirely a bed of roses. Those big Detroit V8s made plenty of power, but buyers often found that it wasn’t enough. To duplicate the impressive elapsed times boasted by the car magazines, or to win consistently at the local drag strip, generally required a low (numerically high) final drive ratio of 3.90:1 or lower, and lower was better.
Trouble was, these racy rear-end gears were far from ideal for street use, resulting in miserable gas mileage, unpleasant highway cruising, and extra engine wear. Turns out you couldn’t have your cake and eat it, too, Not with the available hardware. From that angle, muscle cars were a blast on the weekends and a pain all week. For many, the Motor City’s hot trend of the ’60s was getting old.
Spotting an opportunity, in 1968 the Dana Corporation went to work on a solution. Partnering with the Lincoln-Mercury division of Ford Motor Company, Dana developed a two-speed rear axle assembly for the muscle car crowd—an old idea with a new application. The marketing wizards cleverly it named the Streep, a combination of “street” and “strip.” A dolled-up 1969 1/2 Cougar Eliminator was prepared to showcase the setup.
The Streep was based on a standard production Dana 53 series axle, a stout Salisbury-type unit with a 9.25-inch ring gear that was closely related to the Dana 60. (Ford performance applications then typically used the corporate 9-inch axle we featured here.) The additional hardware in the pinion housing was simplicity itself: a set of spriral-cut gears with a .675:1 ratio, operated by a collar, fork, and cable that connected to its own shift lever next to the driver.
As you would expect, the magazines on the muscle car beat were all over the story. Hot Rod featured the Cougar Eliminator on its January, ’69 cover (below) and then tested it in June, where the axle was paired with a 428 Cobra Jet V8 and a three-speed automatic transmision. The axle provided two final drive ratios, 2.88:1 for cruising and 4.27:1 for acceleration, and the improvement at the drag strip was dramatic: 13.90 seconds through the quarter-mile beams with the tall gear versus 14.43 seconds for the cruiser. Hot Rod issued its thumbs up, and other magazines reported that the feature would be offered on Ford and Mercuy models in 1970 as a $200 option.
That never happened, of course. The deal never went anywhere. While the two-speed axle probably would have been popular (especially at $200) the muscle car trend was already fading, and Detroit’s engineering departments were shifting their resouces from performance to emissions. While the Streep axle was certainly a useful development, it wouldn’t have saved or even prolonged the muscle car era, we don’t think. But it would have made it even more interesting.
I think the muscle car era died for many reasons, including the one mentioned in the story.
High gasoline prices and increasing insurance rates hurt. Government safety mandates added higher cost, complexity, and weight to cars. Auto manufacturers got greedy and raised prices, making it hard for a kid earning minimum wage to afford one.
A lot of wealthier speed freaks were seduced by smaller and sophisticated European, and later, Japanese, cars. Being seen in a V8 American sedan was increasingly uncool.
The environmental wackos gave the stinkeye to anyone during a burnout, and they were loud, smug, and all over TV. The kid in a white t-shirt with his Mopar looked stupid.
In the end, emissions regulations took all the fun out of a high performance cars. Until the advent of engine computers cars were sluggish, shakey, and prone to die at stoplights.
The two-speed rear end would have helped keep the muscle car era alive a little longer, but that era was unsustainable.
I deliberately chose not to enumerate all the reasons for the end of the muscle car trend. That’s a complete story in itself.
Wasn’t this Dana the same rear end as some earlier Fords ’s had in the 1940’s? Ford offered it as a option and was called a “Columbia” rear end. As I recall.., it was an actual over drive rear end.
The Columbia 2-speed rearaxle was made by a company of the same name that was part of the Auburn-Cord-Duesenberg combine. It was offered on Auburn automobiles from the factory and available in the aftermarket for Ford and Lincoln-Zephyr. It used a different type of gearset. There were also a number of two-speed axles for trucks.
Our auto shop teacher at Warren Cousino HS in 1973 used one of these on a project car he was building that also used a Cadillac straight-6 with a turbocharger.
Cadillac never made a straight 6.
$200 in 1970 is about $1,600 in 2023 dollars, so not so sure about that “especially.”
To give you an idea, the 4-speed transmission on many cars of the period was $200-225. Automatic transmission was around the same price.
Seems like this could have been marketed as a fuel saving feature as well, back before overdrive transmissions were common in the early 70s. A missed opportunity
My thoughts, as well. Ironically, I’ve read that Ford had a four-speed overdrive transmission in development between ‘62 and ‘66, stopped work on the project and then resumed work after the fuel crisis in ‘73. Perhaps the advantage to the two-speed rear axle is the ability to install it in both manual and automatic transmission equipped vehicles, and lower development time and development cost.
Exactly. This would work with both sticks and automatics. Dana carries the development cost and Ford doesn’t have to modify its existing transmissions.
I had junkyards back in the 80s and 90s. My 2 – 5 ton scrap hauling trucks had two speed rears like this. I loved them because the low gear would pull fantastic weight whereas high would let you get highway speed. Looks like this one shifted with an electric motor and worm gear? The old trucks had the same setup and you soon got good at repairing them. Mostly the switches to shut down the motor at the end of travel on the worm gear or the electric motor. Took a little while to get the timing right at shifting them at speed but once you did….sweet!
Was that a Columbia rear end? My uncle had it in his old 1040’s Ford. Came as an option. We called it over drive.
With the overdrive behind the speedo gears, a different speedometer would be required like cars had in the 30s. My 36 Chrysler has two speedometers available, one for cars with OD and another for no OD.
Great point. Two customary workarounds are a speedometer with two bands printed on the face, or running the speedo cable from a front wheel, as Oldsmobile did.
And VW that had an overdrive top gear
Nice article!
The “dolled-up 1969 1/2 Cougar Eliminator” is the vehicle that is generally referred to in Cougar circles as the Eliminator Prototype. It debuted in Oct 1968 at the Los Angeles Auto Show (as well as appearing at other auto shows). It was also the vehicle featured in the January 1969 Hot Rod Magazine article. The regular production Cougar Eliminator started production on April 1st, 1969 (sans 2-speed rear axle).
My understanding is that the Streep rear axle was not implemented due to Mercury not being able to make the design sufficiently simple and robust enough for the common consumer (i.e. they anticipated a lot of warranty claims that would erase any potential profit from including this as an option).
I am also told that the system’s gear-changing push-pull cable also operated a speedometer drive ratio change unit.
Thanks again for the great article.
Mike B.
Cougar Club of America
I oce owned a32 Auburn with a 2 speed diff. It was in effect my playhouse when a kid.
Have driven plenty of trucks with a 2 speed diff,,, and heard the ‘graunch’ as trucks drove by our place looking for a big valley, down the hill at maybe 60mph and struggle over the top the other side at about 6mph. This in the 60s and 70s.
A 2 speed diff in ‘muscle cars’ would have been heavy. 9″ already weigh a lot as does the big Canas in Mopars, and their 8 3/4″ were bloody heavy as well. Unsprung weight a real issue.