A Simple Guide to the G80 Locking Differential

Customers in the market for a mid or full-size pickup truck are well aware of the benefits that come with a rear locking differential. In General Motors’ case, the Eaton G80 automatic locking rear axle is the name of the game for the Colorado and Silverado model lineup.
G80 Locking Differential 1 photo
Photo: screenshot from YouTube
This guide is aimed at first-time truck customers and younger enthusiasts, but also acts as a brief reminder to those that can’t imagine towing and hauling without the aid of a locking diff. So what’s an Eaton G80 then?

First and foremost, you’ll want to know that G80 isn’t the official name of GM’s locking rear diff. Everyone calls this bit of equipment G80 due to its order code. Regarding the Eaton end of the deal, these guys are mainly known for making high-spec superchargers.

As a prime example of Eaton’s know-how, the ‘Vette Z06 utilizes an Eaton blower for its LT4 small-block V8. Back to the G80 locking rear diff then. As simply put as possible, a pickup truck that’s used for getting the job done cannot do without this little contraption.

In other words, the Eaton G80 automatic locking differential lets a rear-wheel-drive truck go places traditionally reserved for pickups that benefit from four-wheel-drive. Enhanced traction and control are what the G80 locking differential offers overall.

How does it work? Say you’ve ventured with your 2015 Chevrolet Silverado 1500 off the beaten path, on a muddy field for example. If one of the rear wheels starts to spin looking for traction, the Eaton G80 rear axle locks automatically. This enables both rear wheels to propel the truck out of the muddy situation.

As mentioned beforehand, the diff engages without any input from the driver. When does the G80 lock, you’re asking? When the rear wheel speed difference reaches 120 rpm, thus delivering up to 100 percent of the driveline’s power to both driven wheels for maximum attack. Of course, the G80 differential can also be had on 4x4 pickup trucks for added versatility.

“The G80 locking axle provides a greater traction advantage than limited-slip differentials in most situations, while its automatic engagement requires no driver involvement, unlike some competitors’ electronic lockers, which require driver activation,” said Jeff Luke, GM executive chief engineer. “The G80’s simplicity, durability and sure-footed grip have been proven with generations of customers, as it has been a staple of the Chevy truck lineup for more than 40 years.”

If you insist on going technical, we’re much obliged to tell you that the Eaton G80 performs like an open diff until excessive slip in one wheel triggers the locking mechanism. With both rear wheels rotating at the same speed, this provides better traction than a conventional limited-slip differential. Unlike high-tech electronic lockers, the G80 differential detects wheel slip through some flyweight-type governor.

When slip is detected by the mechanism, a self-energized clutch system forces a camp plate ramp against a side gear, compressing a disc pack. This action causes both rear axle shafts to rotate at the same speed. Instead of “So long, folks!” we deem necessary to mention that the Eaton G80 locking differential comes as standard on the Chevrolet Silverado 1500 LTZ and Z71 models, as well as all Silverado 2500 and 3500 heavy-duty pickup trucks.

Even the mid-size Colorado benefits from it if you go for the Z71 package. The G80 is an optional extra on the 2015 Colorado WT and LT models. Furthermore, full-size SUVs such as the Chevrolet Tahoe and Suburban also benefit from the G80 locking differential’s prowess. If you got lost somewhere in between these lines, the demo video below should clear things up.

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About the author: Mircea Panait
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After a 1:43 scale model of a Ferrari 250 GTO sparked Mircea's interest for cars when he was a kid, an early internship at Top Gear sealed his career path. He's most interested in muscle cars and American trucks, but he takes a passing interest in quirky kei cars as well.
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