As we previously reported, General Motors acknowledges a 10-speed transmission problem. But one company claims to know the real story – and solution.

GM 10-Speed Transmission Recall

General Motors issued a recall (designated #N242454440) for its 10-speed automatic transmissions, including those branded with the “Allison” name.

The core issue involves a potentially dangerous lockup of the rear axle, especially at higher speeds. While General Motors advises that affected vehicles are still drivable, they acknowledge an increased risk of crashes if lockup occurs.

Nature of the Problem and Next Gen’s Involvement

Next Gen Drivetrain, a company specializing in transmission upgrades, claims they alerted General Motors to this safety problem in early 2024, offering a solution. They stated that General Motors generally dismissed or rejected their offers, even at reduced prices.

Next Gen Drivetrain reports documenting many vehicles experiencing this failure, suggesting a widespread issue. They also point out that some dealerships, recognizing the severity, have paid out-of-pocket for Next Gen’s fix after being denied support from General Motors.

List of recalled vehicles

List of the vehicles that have been recalled due to transmission issues:

• 2020-2022 Chevrolet Silverado 1500, 2500, 3500 pickups
• 2020-2022 GMC Sierra 1500, 2500, 3500
• 2021 Cadillac Escalade, Escalade ESV, Tahoe, Suburban; GMC Yukon and Yukon XL SUVs

How the Transmission Fails

The 10-speed transmission uses six clutch packs. A proper gear change needs three packs. The failure occurs when four clutch packs engage at once, creating a bind that locks the transmission’s output shaft and the rear axle.

Technical Explanation and the Fix

According to Next Gen Drivetrain, the problem originates from wear-related cross-leaks within the valve body, which become more pronounced with age. These leaks cause a fourth clutch pack to apply at the wrong time.

If the transmission fluid appears significantly darkened, indicating substantial internal damage, Next Gen Drivetrain advises a complete transmission replacement, highlighting its own upgraded units as superior to standard rebuilds.

Next Gen Drivetrain’s Solutions

Because of the mass transmission recall by General Motors, Next Gen Drivetrain came up with two main solutions. For transmissions with limited wear, they offer a valve body upgrade kit that includes steel valves, new O-rings, a modified separator plate, and solenoid clips.

For vehicles with greater wear or those seeking a comprehensive fix, they recommend a fully remanufactured valve body with all-new electronics.