The GMC Sierra Heavy Duty pickup is all-new for the 2020 model year, and that means extensive changes, both above and below the surface. Now, we’re taking a look at what’s going on underneath this highly capable truck by peeking at the undercarriage.
Looking over these photos, we can see a good deal of the mechanical components. We can also see the fully boxed frame, which provides a sturdy backbone for this powerful workhorse vehicle.
The engine in play here is the turbo-diesel 6.6L L5P V8, part of the Duramax engine family, which lays down an impressive 445 horsepower and 910 pound-feet of torque. The ‘eight mates to an all-new, segment-first Allison 10-speed automatic transmission, which, as we covered previously, isn’t actually an Allison transmission. We also see the optional Autotrac two-speed transfer case, not to mention an absolutely gargantuan drive shaft to help harness the turbo-diesel’s mammoth output.
All told, the 2020 GMC Sierra HD’s larger frame, strong propulsion system, and onboard tech combine to deliver a maximum towing capability up to 35,500 pounds. That’s an increase of 52 percent compared to the previous model-year vehicle.
To note, the 2020 GMC Sierra HD truck is also offered with the 6.6L L8T gas engine, which was introduced as a replacement for the previous 6.0L L96 V8, and produces 401 horsepower and 464 pound-feet of torque. The L8T mates to a six-speed automatic transmission.
Other details we can spot from this low angle include the exhaust pipes and the X31 Off-Road suspension bits, including the Rancho shocks. Don’t forget the braking components, the side step-ups, and the low-mounted spare wheel as well.
Indeed, there’s a lot to pick apart from these undercarriage photos of the 2020 GMC Sierra 2500HD. What stands out to you the most? Let us know in the comments, and make sure to subscribe to GM Authority for more GMC Sierra news, GMC news, and around-the-clock GM news coverage.
Comments
It’s not rusty fom the factory like my 17’ l5p!
I read the linked article about the Allison-branded transmission. How much is GM paying Allison to slap its name on a GM transmission? And isn’t that kind of risky on Allison’s part? Suppose the transmission has a severe design flaw, wouldn’t that hurt the Allison brand even though they weren’t even responsible for developing the unit? I’m just sayin’.
Had a GM rep tell me yesterday that Allison helped design and engineer the transmission but GM decided to bring the manufacturing in house to some some money. I guess we will see how it plays out
That’s the same way I understand it, co-developed, manufactured by GM.
GMA acts like Allison had nothing to do with it.
It’s Allison designed, engineered and benchmark tested. It is thus an Allison transmission. It is only manufactured by GM as opposed to Allison. That way GM saves money by making it In house and Allison can focus on high margin low volume transmissions for tanks and dump trucks.
I believe General Motors owns part of Allison if I am not mistaken, so they don’t have pay Allison any ransom money to put their name on it.
I think they may have owned it back in the day but sold it
they probably powder coated the frame for show
Yes, I think GM still uses that messy Nox-Rust wax coating on their frames.
It’s got lots of Allison DNA in it. Also, for the last several years at least, GM was building the Allison 1000’s they used at a plant in Baltimore, Allison 1000’s used in other nameplates pretty sure came from Indy. I questioned the Allison branding until I saw inside one of them, it’s way more Allison than GM.
Yes, that’s my understanding. Some were saying the Allison 10 speed is related to the new Ford 10 speed Torq-Shift, but I don’t think it is.
gm and ford 10 speeds are the same internally they partnered on engineering it they did do there own programing though
That’s true for the 1500’s and F-150, but the 10 speeds used in the HD’s and Super Duty are different. What is interesting is the Ford 10 speed Torq-Shift (10R140) used in the Super Duty is something of a scale-up of the light duty 10 speed GM and Ford partnered on. The Allison 10 speed is a different animal.
that’s interesting I didn’t know what ford used in there hds sales manager told me the gm hd 10 speed was not made by allison but re engineered by allison based on the car/ld version. I would usually think they say hell yes allison all the way best in the business
at every turn GM cost cuts, fake transmission, cheap black plastic all over the exterior, You can get any color interior you like as long as it is a Black interior. all paint colors are now dark colors as to hide the cheap black plastics. cheap re-hashed truck year after year. cheap blown plastic interiors. JUNK
The GM HD 10 speed ‘Allison’ has absolutely nothing in common with the Ford HD 10 speed or the LD 10 speeds other than having 10 speeds. And no way is this a cost cutting move. Developing an all new 10 speed and then getting Allison to test and re engineer the weak bits when they could have just kept using the 20 year old 1000 series design is hardly the ‘cheap’ way.