No, It Doesn’t Have Positraction

James Kraus

JK - 1 (15)

1964 Pontiac GTO Sports Coupe in Sunfire Red metallic. Equipped with optional triple dual-throat carburettors, four-speed all-synchromesh gearbox and Safe-T-Track.

Few things warm the hearts of Car Nutz like good punchy buzzwords. Favourites of American car fans include Muscle Car, Big Block, and today’s topic; Positraction.

Legions of American car enthusiasts enjoy (or would like to enjoy) boasting of owning (or having owned) a car with Positraction. See how it rolls off the tongue? It’s a spartan one-word expression, bursting with masculine hard consonant sounds.

Unfortunately, few cars during the heyday were actually available with Positraction. Here is a handy list of all car models which offered it as an optional extra:

150 Chevy II Kingswood
210 Corvair Nomad
Bel Air Corvette Nova
Brookwood El Camino Parkwood
Caprice Handyman Yeoman
Chevelle Impala

Notice any commonality here? That’s right, they are all Chevrolets! No other automobiles (except Canadian Pontiacs with Chevrolet drivetrains) came with the alluring and mystical Positraction, the feature mythologized in song:

My four-speed, dual-quad, Positraction 409  –  The Beach Boys, 1962

What was this magic elixir that was Positraction? It was simply an optional limited-slip differential introduced by Chevrolet for 1957.

1957 Chevrolet Positraction brochure.

Volkswagen had been offering a ZF limited-slip differential since the early 1950s, but Chevrolet and Studebaker were the first U.S. manufacturers to offer such an item. Studebaker’s offering was sold under the less-sexy name Twin-Traction. 

Two other manufacturers quickly followed suit in 1958 with Pontiac offering Safe-T-Track and Rambler Powr-Lok. The following year saw the introduction of Ford’s Equa-Lock, Mercury’s Power-Transfer, Lincoln’s Directed-Power and Chrysler Corporation’s Sure-Grip.

1958 Pontiac optional features brochure

In 1960, Oldsmobile debuted Anti-Spin and Buick, Positive Traction. By 1962 Cadillac owners could avail themselves of a Controlled Differential.

The Beach Boys’ 409 single released 4 June, 1962.

None of these other marketing monikers mattered however, because in June of 1962 The Beach Boys released their immortal 409. As soon as the song landed in the Billboard Hot 100, every hotrodder, car nut and adolescent male wanted a car with the beguiling sorcery of Positraction, even if many of them had only the foggiest idea of what it was.

“Why this here ’64 GTO auto-MO-bile has the original Tri-Power, 4-speed, and Positraction!”

Of course, Pontiacs never came with Positraction. They came with Safe-T-Track. Your buddy’s ’65 K-Code Mustang doesn’t have Positraction, and likewise neither does that ’66 Oldsmobile 4-4-2 you spotted last month.

Major auction houses usually get it right, but not so with the average Joe. Or Hollywood: In My Cousin Vinny, Marisa Tomei testifies that dual equal-length tire marks revealed in an evidence photo could not have been made by a ’64 Buick Skylark “Because Positraction was not available on a ’64 Skylark.”

However, the Skylark was available with Buick’s Positive Traction and the ’63 Tempest she alluded to was similarly unable to be ordered with Positraction, only with Safe-T-Track. Points the prosecution could have raised to sow the seed of doubt in the minds of the jurors!

Buick mistakenly used the term Positraction in a 1969 brochure and was quickly censured by the GM legal department. It never happened again.

To this day, the majority of American cars fitted with a limited-slip differential are consistently claimed to be endowed with Positraction or it’s casual diminutive, Posi. But unless they are wearing a bowtie badge, they don’t have it.

6 thoughts on “No, It Doesn’t Have Positraction

  1. It’s like a hoover not being a Hoover I guess. A browning not being a Browning. In French a frigidaire, a Frigidaire. These things get out of hand. And a DS not being anything near a Citroen DS. But I’m deviating.

  2. Wikipedia has an entry for positraction as a generic term for limited slip differential, but lists the commercial names under which this equipment was sold by the different car makers. The term seems to have gained wider acceptance, more so than LSD, which by the late ’60s referred commonly to something else.

  3. Glad to see this! Picky for some, when you need a clear understanding for a particular installation. Chasing the wrong name could cause many hours of misunderstandings….

    I am curious…What do you call a limited slip differential in a Chevrolet rear end, swapped to a non-Chevrolet? Previously “Positraction” rear end? 🙂

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