2020 GMC/Chevrolet Diesel Engine
“The optional engine remains the largely carryover 6.6-liter Duramax V-8 turbo-diesel—445 horses and 910 lb-ft—but is now mated to a 10-speed version of the excellent Allison automatic gearbox, up fro...
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I had an 8 speed and the extra speeds were really just noticed when starting from a stop. No hunting at highway speeds. I loved mine.
