C/K Man

Starting to hear some sketchy unverified rumors about the next gen. HD's, which some are saying should debut late next year: Revised Duramax (some say will still be a 6.6L) and a new gasoline engine, possibly an iron-block Gen VI of unknown displacement. It seems that the Gen. VI's can accommodate a longer stroke than the current Gen. V, so read into that what you will. Revised chassis also featuring the new E-coat as the light duty 2027's will have. The current HD chassis dates to 2011 with a few minor modifications over the years. A medium duty 4500/5500/6500 derivative that will replace the current Silverado Medium Duty. The next gen. HD's will possibly be built at Flint and Oshawa, and medium duty production will move to a GM plant from the International plant, which is in the process of closing. Post whatever HD rumors you hear and we'll see how accurate they turn out to be!

GM is moving away from the wax frame coating: https://gmauthority.com/blog/2026/06/2027-chevy-silverado-gmc-sierra-1500-get-new-frame-coating/

https://gmauthority.com/blog/2026/05/is-this-gmc-sierra-hd-prototype-testing-a-new-gm-gas-engine-for-heavy-duty-trucks/

Is Oshawa building LD's too? It will be interesting to see what will happen in Fort Wayne, that's where most U.S. LD's are made I believe.

Work is the Silverado Medium Duty trucks are being dropped. Dearlers are still taking orders but production ends on September 30th.. The reason seems to that International has sold the Springfield plant where these trucks are manufactured. The Isuzu based LCF models will continue. Rumor is GM may introduce new medium duty models with the 2029 Silverado HD's. The trucks will likely be produced by GM without a partner.

That is a flap that goes on either end of the cowl vent at the base of the windshield. Normally you can't see it because it is behind the fender. It is supposed to let water out of the cowl but keep hot air from the engine compartment from being drawn into the HVAC. It has a little weight on it to keep it closed.

I would like to see them bring back the E-85 option.

Monroe Equipment was the company that converted the Topkick and Kodiak.

You need a scanner that can read the ABS/stability/trailer brake systems. These are 'C' codes. If there isn't a trailer hooked up the problem could be with the plug if it isn't with your 3rd. brake light.

Sorry, should have said for 2027. I have heard rumors the Gen. 6 for the 1500's and SUV's will be in the form of a 5.7L and a 6.6L.

Any more news on the upcoming L8S? Will it be used in the 2028 HD's or is it the new 6.6L rumored for the 1500's in 2027?

'TFL' ran a piece featuring some footage of test trucks spotted in Colorado recently, and speculated that these trucks may have been powered by the 8.3L Duramax: https://tfltruck.com/2025/07/spied-are-these-the-new-2027-chevy-silverado-hd-gmc-sierra-hd-duramax-trucks-could-they-have-the-8-3l-megamax-v8/ A few days later, 'GMAuthority' posted word from a reliable source that the trucks were in fact powered by updated 6.6L Duramax diesels, and the rumored 8.3L is NOT planned for the HD pickups: https://gmauthority.com/blog/2025/07/is-the-8-3l-duramax-megamax-hiding-in-new-silverado-hd-sierra-hd-prototypes/ FWIW, I think the 8.3L Duramax does exist and is in the pipeline, but I think it's for larger commercial trucks.

I wonder if Fort Wayne will continue to build Silverado/Sierra LD's or will change to something else: https://www.wxyz.com/news/gm-moving-production-of-escalade-silverado-sierra-to-orion-assembly-plant-in-2027?fbclid=IwY2xjawLj0C1leHRuA2FlbQIxMQBicmlkETFXa3ZVc2tkakV1akxmZTdaAR4DvhDAc_l-S2xL7EtjddTFPja7i_md_WhZld8YamgVpixZNoFnKIjHf9RWEA_aem_c2TaGgBU7d_ZJJ-Sr-trEg

CAFE has to do with fuel economy, not emission controls. Emissions is EPA and CARB.

So, if the Corporate Average Fuel Economy requirements are essentially eliminated, what does in mean for the next generation Silverado/Sierra?