It’s no secret that the GM 8-speed transmission is not great. Also known as the 8L90 and 8L45, the 8-speed pairs to rear-wheel-drive architectures in GM’s bread-and-butter products, including pickup trucks, SUVs, sports cars and luxury cars, and to say that it has a few issues would be a major understatement. Owners have complained far and wide about the 8-speed’s strange tendencies, such as waiting too long to upshift, downshifting at odd times and lurching when coasting or coming to a stop light. Long story short, GM needs to do away with the 8-speed and replace it with the much-improved 10-speed automatic… and quick.
In fact, GM was recently slapped with a class action lawsuit over the 8-speed gearbox. The plaintiffs assert the GM 8-speed transmission is defective, creating violent shakes, jerks, and a “hard shift” when selecting a gear. For its part, GM has filed 13 technical service bulletins concerning the unit, none of which remedied the issue. Following the lawsuit, more owners have spoken out over the issue, and we’ve even heard from our own readers about it on our forums.
The issue seems to be most common when accelerating or decelerating as the transmission tries to find another gear, with the problem believed to stem from the torque converter as well as the gearbox’s shifting logic.
Following a litany of complaints, GM tried to “improve” the 8-speed in the 2019 Silverado and 2019 Sierra. In a press release, the automaker said it made “enhancements designed to improve shift quality, while also adding a new centrifugal pendulum absorber torque converter” to improve smoothness. The new revised transmission was assigned RPO code MQE, replacing the M5U 8-speed unit on the half-ton Silverado and Sierra, but not (yet) on other GM products like full-size SUVs or mid-size pickups.
Taking all that into consideration, The General seems to have grossly mishandled the entire situation with the 8-speed transmission. What it should have done is replaced the GM 8-speed transmission outright with its new 10-speed automatic (jointly developed with Ford) in every vehicle application. Of course, that would have required some doing, as the GM product lines that would qualify for the change-over today include:
- The 2019 and 2020 Chevrolet Silverado 1500 as well as the 2019 and 2020 GMC Sierra 1500 equipped with the 2.7L turbocharged four-cylinder L3B engine and 5.3L V8 L84 engine, with other engines being paired to either the 6-speed or the new 10-speed.
- The entirety of the full-size SUV lineup, including Chevrolet Tahoe, Chevrolet Suburban, GMC Yukon and Yukon XL, as well as the Cadillac Escalade and Escalade ESV. All of these will soon be replaced by all-new models for the 2021 model year, and here’s to hoping that GM doesn’t continue offering the 8-speed on lower-end trims.
- Chevrolet Express and GMC Savana models equipped with the 4.3L V6 LV1 engine.
- Sixth-generation Chevrolet Camaro LT equipped with the 2.0L turbocharged four-cylinder LTG engine
- Second-generation Chevrolet Colorado and GMC Canyon
Previously, the GM 8-speed transmission was also used in sunset models like the Cadillac ATS, third-gen Cadillac CTS (except for the CTS V-Sport, which used an Aisin eight-speed), and the 2016-2018 Cadillac CT6 (the vehicle switched to the 10-speed transmission for the 2019 model year). In addition, the GM 8-speed transmission was also used in the 2016-2018 Camaro LT and SS, along with the now-discontinued C7 Corvette (apparently the 10-speed was too wide to fit into the C7).
The GM Authority Take
To play armchair quarterback for a quick minute, The General should have bitten the bullet and replaced the GM 8-speed automatic transmission in any applicable vehicles with the new 10-speed unit as soon as the new 10-speed was launched, no matter if the model was due for an update, refresh, or overhaul, or not. Instead, The General dug its heels in and continued to offer vehicles with the lackluster 8-speed, going so far as to launch all-new products – most notably the 2019 Silverado and 2019 Sierra – with the 8-speed that was “improved,” but that didn’t deliver any noticeable improvements.
Sure, switching to the 10-speed mid-stride would have created additional expenses and required additional engineering work. So yes, it would have cost GM money. But wouldn’t those funds have been well-spent when compared to the gobs of money GM will probably end up spending in legal fees to defend itself (and potentially pay out on the class action), while also causing reputation-based damage as a result of customer dissatisfaction in its bread-and-butter products, thereby potentially losing customers for life?
Why, yes it would have.