Tesla is gearing up for high-volume production of the Semi later this year, and to showcase just how far development on the electric Class 8 has come, Jay Leno got hands-on with the latest production-intent vehicle.
In a new 47-minute video, Tesla’s Chief Designer, Franz von Holzhausen, and Semi Program Director, Dan Priestley, walked Leno through a massive list of under-the-hood engineering upgrades, structural changes, and fleet data that prove the Semi is finally ready to disrupt the diesel industry.
Shedding Weight & Boosting Efficiency
One of the most significant revelations from Priestley is that the engineering team managed to shave roughly 1,000 pounds from the newest iteration of the Semi. For fleet operators, shedding that much weight is a massive value driver, directly translating into increased payload capacity and reduced energy consumption.
Because the Semi is legally granted a 2,000-pound weight exemption as an electric vehicle, this 1,000-pound reduction puts the 500-mile Long Range version nearly on par with traditional diesel trucks in terms of total hauling capacity. When it comes time to recharge, Priestley confirmed the Semi can handle speeds up to 1.2 megawatts, allowing the truck to recover 60% of its massive battery in just 30 minutes.
Cybertruck Tech & 4680 Cells
As the Semi moves toward mass production at Tesla’s new facility outside of Giga Nevada, Tesla is adopting several major engineering breakthroughs pioneered by the Cybertruck.
The Semi now uses a fully electric steering assist system, abandoning the traditional hydraulic assist found on earlier models. While it is not a pure steer-by-wire system, it borrows beefed-up steering actuators directly from the Cybertruck to handle the massive weight of the vehicle.
Tesla's @danWpriestley has revealed more information abbot the redesigned Tesla Semi:
— Sawyer Merritt (@SawyerMerritt) March 23, 2026
• Now uses fully electric steering assist (vs hydraulic before)
• Uses beefed up Cybertruck actuators
• 48 volt architecture
• 4680 cells, designed to last 1M miles
via Jay Leno's Garage pic.twitter.com/xh6rZ9mZ0q
Additionally, the Semi has officially transitioned to a low-voltage 48-volt architecture, stripping out massive amounts of heavy wiring harnesses and greatly improving manufacturing efficiency.
Powering the drivetrain is a structural pack made of Tesla's 4680 lithium-ion battery cells. According to Priestley, this pack is designed to outlast the typical lifecycle of a commercial truck, engineered to endure 1 million miles with minimal degradation.
In addition, the battery pack is cube-shaped rather than spread out flat, as in other Teslas. This helps it retain heat in cold conditions, preventing the truck from using battery power to keep the battery warm when it’s left idle for longer periods. Tesla also split out the battery pack cooling so that it’s now independently controlled.
Dedicated Torque Axle
Perhaps one of the most interesting engineering details revealed during the show is the Semi’s powertrain architecture. Rather than relying on a complex multi-speed transmission, the Semi utilizes a clever dual-axle setup with distinct gearing purposes.
The front torque axle is geared specifically for heavy acceleration and pulling massive loads up steep grades. Once the truck reaches highway cruising speeds, this torque axle completely disengages internally to eliminate mechanical drag. A separate efficiency axle then takes over to handle all highway cruising. This solution perfectly balances the need for low-speed pulling power with high-speed, long-haul efficiency.
Standard vs. Long Range
We now have a good look at the Standard and Long Range variants of the Tesla Semi.
While Leno spent most of the episode driving the 500-mile Long Range Semi, Priestley also introduced the highly anticipated Standard Range model, which boasts 325 miles of range per charge.
The primary difference between the two models lies in the battery packs. The Long Range version uses three battery modules in parallel, whereas the Standard Range uses two.
This allows Tesla to significantly shorten the wheelbase of the Standard Range model. As a result, the 325-mile Semi is lighter, cheaper, and more maneuverable, featuring a tight turning radius that Priestley noted is about the same as a Tesla Model Y.
Tesla says the Tesla Semi Standard Range (325 mile range), which has a shorter wheelbase than the Semi Long Range (500 mile range), has about the same turning radius as a Model Y.
— Sawyer Merritt (@SawyerMerritt) March 23, 2026
Jay Leno driving the redesigned Tesla Semi in his new video: "Nice turning radius. Boy that's… pic.twitter.com/KZCDWTqxNo
During rides, it’s common for drivers to comment on how good the turning radius is, but they’re only 3/4 of the way to lock. I’ll chime in “oh you can keep going” and they turn the wheel more and are blown away. Maneuvering in tight urban spaces is critical.
— Dan Priestley (@danWpriestley) March 23, 2026
Wireless Charging Potential
When it comes time to recharge, Priestley confirmed the Semi currently utilizes 1.2-megawatt fast charging to recover 60% of its battery in just 30 minutes. However, the Semi engineering team is also looking toward a wireless charging future.
During the walkthrough, Tesla flagged automated wireless charging as a future opportunity for the Semi. By allowing the massive truck to simply pull over an inductive pad at a depot or loading dock without requiring a driver to manually wrestle with heavy, liquid-cooled cables, Tesla could streamline fleet turnaround times.
This builds on the same wireless charging technology Tesla is currently developing for the upcoming Cybercab network.
Refrigeration Units / Powershare
Tesla uses a modified version of Powershare from the Cybertruck to allow the ability for the Semi to power refrigerated trailers. While most diesel trucks include a separate generator to keep refrigerated trailers cool, the Semi can do it all without any additional hardware — just plug it in. This not only saves on additional hardware but also on cooling costs.
Since this is simply an electrical hookup, it also isn’t limited to refrigeration. It could power an RV, or other types of trailers.
Unmatched Fleet Reliability
Beyond the hardware upgrades, Tesla brought receipts to prove the Semi’s viability. While the public rollout has seemed quiet over the last two years, Tesla has been steadily accumulating a mountain of real-world data from its pilot program partners.
According to Priestley, the current test fleet of a few hundred trucks has already logged over 13.5 million miles, with the lead truck sitting at nearly 440,000 miles. The fleet is currently boasting an incredible 95% uptime.
When breakdowns do occur, Tesla’s service network has been highly responsive; 80% of issues are resolved, and the truck is returned to the customer in under 24 hours, with half of those being fixed in less than an hour.
You can watch the entire video here:
