The newest advances with the MLocker differential are intended to move it onto future electric vehicle platforms.

Creating an innovation on a blank sheet of paper is challenging enough.

But what if the task is to innovate an existing vehicle component over and over and over for 50 years?

That has been the challenge of engineers and product management at Eaton Corp.'s Vehicle Group when it comes to the MLocker, a mechanical locking differential for trucks that the power management supplier first produced in 1973 for General Motors.

A locking differential establishes a link between both wheels of an axle in case one of them is not getting traction. By locking them, both wheels can deliver torque to pull out of a muddy field or climb across rocky ground, for example.

It's commonplace technology today. But it was a breakthrough for mass-market driving applications in the early 1970s — an era when brawny trucks were still not household fixtures. High-end sports car engineers had begun to seek better axle control to combat spinout while cornering at high speeds. Eaton instead focused on allowing trucks to handle snowy farm roads and off-road terrains where one wheel might be off the ground while the others turned.

But delivering the half-century-old achievement was not the end of the innovation story for Eaton. It was just the beginning.

"We have to continue to improve it, generation after generation," Mark Kramer, Eaton's business unit director for ePowertrain, told Automotive News. "Especially now. Nobody foresaw the truck market taking off like it did. Originally, the differential was something of a special feature. Today, it's an important component, and it's also a critical product for us."

A 1973 advertisement for Eaton’s MLocker

Among the innovations over the decades:

One recurring cause for design change: the MLocker had to account for the steady rise in torque and horsepower on new trucks.

"Just think of a Silverado that you're driving around today," Kramer said. "That torque has gone up significantly over the past 30 years. So everything needed to get bigger to account for it all."

Only about a fifth of Eaton Corp.'s global business is automotive. But of Vehicle Group's $2.58 billion in sales last year, differentials accounted for about 20 percent, Kramer said.

That represents a critical business for Eaton.

"We have a dedicated team of engineers and we have a proving ground in Michigan," said Kramer, who at 41 is younger than the product.

"We also have a team of engineers in South Korea, a team of application engineers in China and a team in Prague that does testing," he said. "So we have global resources dedicated to this differential product line."

Eaton's newest innovations are intended to move the MLocker onto future electric vehicle platforms.

Potential EV makers want the MLocker, but they need it to be lighter, more efficient and with less friction — which might sap battery range. Lubrication also is an issue. The differential normally gets a constant bath of axle lubrication — EV makers want lubrication to be sprayed on when necessary.

"This product is important to us," Kramer said. "Every four or five years, as new trucks refresh, we will have to make it bigger, make it better, make it quieter and just make it perform better."

Have an opinion about this story? Click here to submit a Letter to the Editor, and we may publish it in print.

Please enter a valid email address.

Please enter your email address.

Please select at least one newsletter to subscribe.

See more newsletter options at autonews.com/newsletters. You can unsubscribe at any time through links in these emails. For more information, see our Privacy Policy.

Sign up and get the best of Automotive News delivered straight to your email inbox, free of charge. Choose your news – we will deliver.

Get 24/7 access to in-depth, authoritative coverage of the auto industry from a global team of reporters and editors covering the news that’s vital to your business.

The Automotive News mission is to be the primary source of industry news, data and understanding for the industry's decision-makers interested in North America.

1155 Gratiot Avenue Detroit, Michigan 48207-2997

Automotive News ISSN 0005-1551 (print) ISSN 1557-7686 (online)

Fixed Ops Journal ISSN 2576-1064 (print) ISSN 2576-1072 (online)