It’s time to put the new 2024 Chevy Silverado HD 2500 with the 6.6L (L8T) gas V8 on the world’s toughest towing test – the Ike GauntletTM. We also compare it directly against the 2024 GM HD Duramax turbo-diesel V8-powered truck. We pull the same identical 5th-wheel toy-hauler camping trailer that weighs about 14,000 lbs up and down the tallest and steepest interstate in the country.
2024 Chevy Silverado HD
This is a midcycle refresh for GM’s heavy-duty pickup truck lineup. The 2024 Silverado HD LTZ has a new exterior and interior design. The 6.6L gas V8 is upgraded from the older 6-speed automatic transmission to the new 10-speed Allison-branded transmission. Can the latest transmission make that much of a difference and turn this gasser into a very capable towing rig? Let’s find out!
Thanks to Complete Trailers and GenY Hitch for making this episode possible.
Naturally, the 6.6L Duramax V8 is more powerful and capable, but it also costs $9,500 more than this base gasoline engine. Why not save some money and go with a traditional V8?
The 6.6L gas V8 (that I nickname “Tiger-Jet”) is a 5th-generation LT-family engine. It’s a small block push-rod engine with direct injection. It combines the tried and true features with the latest engine cooling and fuel injection tech. It’s rated at 401 horsepower and 464 lb-ft of torque. It does not offer cylinder deactivation, and this engine has a good reliability record so far.
Ike Gauntlet
This is an 8-mile stretch of the I-70 in the Colorado Rocky Mountains. It goes up to the continental divide and the Memorial Eisenhower / Johnson tunnels at 11,158 feet above sea level. The maximum incline is a 7% grade. Kase and I happen to run this during one of the hottest August days of the year. The ambient temperature was reading 75 F near the top of this run.
Downhill
Naturally, this truck does not have an exhaust brake to help with slowing it down (it’s not a diesel). However, the 10-speed automatic transmission does very well with grade-shifting. It downshifts with confidence on the way down the mountain and gives the engine its best chance to help and slow down this 14,000-lb ATC Game Changer toy hauler. We loaded a Polaris Ranger (3-seater) inside the trailer.
Many gasoline V8 trucks we have tested needed 10 brake applications to descend the 8-mile stretch. This 2024 Silverado HD needed just six brake applications to keep the speed in check. This is a good performance.
Uphill
The high elevation of the Ike Gauntlet robs naturally aspirated engines of power. Our Banks Data Monster gauge showed Ambient Air Density (AAD) at 66%. It means 34% of density and potential power is gone. The truck made it up the mountain in just over 10 minutes. This is two minutes slower than a Duramax V8 truck with the same trailer, but it is also way quicker than the last 2020 Silverado HD 2500 gas V8 we tested with a gooseneck trailer. The new 10-speed automatic is helping.
In the end, I would purchase this gas V8 combination in a truck with fewer options and features in order to keep the curb weight of the truck lower and its payload higher. This Silverado HD 2500 LTZ 4×4 has a payload of just over 3,200 lbs. If this was an LT or a Custom – it would be a bit lighter. If you plan on towing occasionally and you tow a trailer under 12,000 lbs – the gas V8 is a good choice. If you tow often, and you tow heavier – then it makes more sense to spend $9,500 more and get the diesel.
Join us in the video below.
