• Driving the 2018 GMC Yukon Denali with the 10-Speed Automatic: How Different Is It?


    2018 gmc yukon xl denali 10-speed automatic transmission
    2018 GMC Yukon Denali

    The 2018 GMC Yukon Denali and Yukon XL Denali get several updates for the 2018 model year, and the most noteworthy is the addition of the new 10-speed automatic transmission. Gone is the older 8-speed, but the 6.2L V8 is still there. How does the new Yukon Denali drive? Check out this first drive review.

    The big V8 still produces 420 hp @ 5,600 rpm and 460 lb-ft of torque @ 4,100 rpm and keeps the cylinder deactivation mode, which allows it to run in V4 mode. The 10-speed automatic has been unique tuned for the Yukon and Yukon XL. You may know that GM and Ford developed the 10-speed transmission together. Ford uses their version in the F-150, Raptor, Expedition, and the Mustang. GM now uses their version of the transmission in the Camaro ZL1, the Yukon Denali lineup, Tahoe RST, and the Cadillac Escalade.

    GM says, the GMC Yukon’s transmission has unique mounting hardware and software calibration to satisfy the needs of the Yukon Denali customers. In case you are curious, GMC is matching a 3.23 rear axle gear ratio with the new 10-speed automatic.

    In the end, the updated 2018 Yukon Denali drives in a very similar way to the 2017 Yukon with an 8-speed. The gear changes are quick and smooth. The transmission behaves smoothly in easy around-town driving, and it can also execute quick and precise downshifts. However, the overall driving experience is still very familiar. If you were given two GMC Yukons: one with an 8-speed and the other with a 10-speed, you would be hard pressed to identify which one you were driving, if you didn’t use the manual shifting mode and saw the “9” and “10” gear selection.

    Some of you may be happy to know that the 2018 Yukon Denali does not offer engine start/stop. However, the new 10-speed has a Tow/Haul mode and automated downhill Grade Braking feature. If you are going down a significant hill and are using the brakes for a certain amount of time, the Grade Braking feature will automatically downshift and use the engine/transmission to help slow you down.

    The 2018 Yukon XL with the 10-speed gets a slightly better EPA fuel efficiency rating: 14 / 21 / 16 MPG. Check out the image for comparison.

    At this time, only the premium Yukon Denali models are getting the 10-speed automatic. Other 5.3L and 6.2L V8 models stay with a 6-speed or an 8-speed transmission.

    Other 2018 Yukon Denali updates include a new front grille and different wood treatment on the interior. The Denali is also available with features such as: heads up display, adaptive cruise control, lane departure warning, power-folding steps, integrated trailer brake controller, and more.

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    Andre Smirnov
    Andre Smirnov
    Andre Smirnov is an Automotive Enthusiast, Producer, Reviewer, Videographer, Writer, Software Engineer, Husband, Father, and Friend.

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    36 thoughts on “Driving the 2018 GMC Yukon Denali with the 10-Speed Automatic: How Different Is It?

      1. “automated downhill Grade Braking”.

        Sounds a lot like automatic engine brakes.

        Don’t say I didn’t say it first.

        Oh goodness.

            1. You do know that people would pay a LOT more attention to your posts if you didn’t come off as an ignorant brand basher right?

      2. Yeah, the 8 speed and the 10 speed feel the same?

        Except, the 10 speed has automatic engine braking.

        HELLO, big difference!

        And interesting that Ford does not have this in their version of the 10 speed.

        Like I always say, Ford is… well, you know by now.

        1. It’s a huge body-on-frame SUV. 21 MPG is great considering you have a big 6.2L V8 making 420 horsepower and 460 lb-ft of torque. Especially when the 10-speed means you’re always in the powerband.

          Falls in line with the competition too:

          2018 Ford Expedition MAX 4×4: 16 city /21 hwy / 18 combined mpg

          Oh and interesting what Ford has printed in the manual for the 2018 Expedition (and practically every owners manual for 3.5EB equipped vehicles):
          “For best overall vehicle and engine performance, premium fuel with an octane
          rating of 91 or higher is recommended. The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when
          towing a trailer.”

          “Do not be concerned if the engine sometimes knocks lightly. However, if the
          engine knocks heavily while using fuel with the recommended octane rating, contact an authorized dealer to prevent any engine
          damage.”

          Which is essentially the exact same thing GM says regarding vehicles equipped with the 6.2: “For the L86 6.2L V8 engine, premium unleaded gasoline meeting ASTM specification D4814 with a posted octane rating of 93 is highly recommended for best performance and fuel economy. Unleaded gasoline with an octane rated as low as 87 can be used. Using unleaded gasoline rated below 93 octane, however, will lead to reduced acceleration and fuel economy. If knocking occurs, use a gasoline rated at 93 octane as soon as possible, otherwise, the engine could be damaged.”

      3. The Suburban RST also has the 6.2 and would be a compelling alternative. However, the one I really want to see tested is the Suburban 3500 HD Fleet with the bulletproof 6.0 and heavy duty 6 speed auto. That’s one tough truck. The 6.0 makes less power at 360 hp and 380 lb.-ft. but it’s a much heavier duty engine.

    1. My Tundra which is only 165Lbs lighter gets 16 city, 20 highway and 17mpg combined with a 6 speed on regular fuel. This gets worse fuel mileage on premium with a 10 speed.

        1. I took that off the 2018 Toyota website. Assuming you are right the premium still costs more per mile making this the least cost effective V8 on the market and I know many like to praise this truck or should I say engine for good mpg. Just rather ridiculous if you have a brain.

    2. GM should be flogged for their silly engine/transmission restrictions. Really, a $50k comes with a 5.3L 6 speed?

        1. The 5.3 gives a good balance of fuel economy and power. Not to mention extremely reliable (other than the first gen AFM version that had a few minor issues). It’s certainly been a better engine than that trainwreck known as the 5.4 Triton. Anybody that has driven a truck with the latest 5.3 can tell you it isn’t a dog. Especially once it has spent 5 minutes with a tuner.

    3. Just noticed! The 2017 EPA test was performed with regular gas while the 2018 test was with premium gas. Perhaps that helped raise the 2018 highway mileage as well as the new 10 speed transmission did. I also wonder if the curb weights are the same for both years?

      1. The Tundra is a gas guzzler, but not that much worse than this Yukon. Considering the Tundra comes with a 4.30 rear end and doesn’t need to shut off half of its cylinders 15mpg combined isn’t bad!

        1. Keystone the 6.2 is said to develop engine knock under heavy load using regular fuel. This epa rating was also done with premium fuel so what is the mpg on regular fuel?

          Take a look at say 15mpg over current fuel prices in Colorado 2.45 regular and 2.90 for premium over 10,000 miles a year.

          My Tundra costs 10,000/15×2.45 = 1,633.33
          6.2GM 10,000/16×2.90 = 1,812.50

          Therefore the worst Truck socially speaking for poor mpg the Tundra costs less to drive per year than the 6.2 can deliver. We also have to look at rounding, if the 6.2 scored 15.5mpg than it rounds up to 16mpg, if the Tundra had 15.4mpg it gets rounded down to 15mpg so this idea that the 2018 scored 1mpg better than the 2017 could be very false and misleading without decimal places.

            1. But then you risk engine knock as per the owners manual under hard acceleration. The motor would do nothing but knock for me constantly with my heavy foot if I ran regular. Then how long before maintenance becomes an issue. A better motor would be the 6.0 in the HD or the 5.3.

            2. The Real Jay S, that 1 could be 1.9mpg or 0.1mpg so it is very misleading to say the premium helped by 1 mpg on the highway which is why the rounding even out as they include for more decimals.

              If the 2017 truck was at 19.5mpg it rounds to 20 mpg as recorded and the 2018 was at 21.4mpg then it records at 21 mpg which is a 1.9mpg difference. If the 2017 truck was at 20.4mpg and the 2018 at 20.5mpg then do the math, 0.1mpg difference.

              Same for the Tundra, we don’t know if there is a 0.1mpg difference or a 1.9mpg difference between the GM 6.2 and the Tundra.

            3. I don’t understand how journalists can say one truck beats the other based on epa when there could be only a 0.1mpg difference between the 2. Same goes for a 2mpg difference, it would actually only be a 1.1mpg difference or a 2.9mpg difference, we don’t know. Kind of ridiculous to pick a truck based on mpg anyways when they are so close. Just tired of hearing how great the 6.2 is on fuel and the Tundra gets shit on but they are virtually the same and you need premium for the GM

            4. Worst case for me Jay is this
              Tundra Gas vs 6.2 GM

              10,000/14.5×2.45 = 1,689.65
              6.2GM 10,000/16.4×2.90 = 1,768.29

              or best case

              10,000/15.4×2.45 = 1,590.90
              6.2GM 10,000/15.5×2.90 = 1,870.97

              Or you use regular fuel in the 6.2 and still have little to talk about with potential for engine knock.

          1. I concur with your numbers Rambro and also think you have a great point about the mpg rounding. At any rate, I’m not the slightest bit impressed with the numbers achieved by the GM 6.2 and wouldn’t be comfortable with the thought of risking engine knock or potential damage by running anything less than premium fuel. I really wasn’t concerned with mileage when I bought my Tundra. I just wanted a reliable and powerful truck and that’s exactly what I have. Also sounds awesome as well!

            1. If you are going to feed the 6.2 87 octane fuel, you should have just bought the 5.3.

              I’m pretty sure a 5.3 running on E85 (380 hp/416 tq on E85) is probably making around the same power as a 6.2 on 87 octane once the 6.2 pulls timing to reduce knock.

              The GM DI engines really don’t like 87 octane, even the 5.3. They all pull timing on 87. They are much happier on mid-grade or premium fuel.

              I agree that the 6.2 has a higher cost per mile than other engines that are designed to run on 87.

    4. Well I am most curious to see if there is any truth to the the automatic grade braking. Ford’s version of the same transmission hasn’t proven to be anything special downhill so if it works better for gm it must just be a software thing. Perhaps a little advantage for gm too with the 6.2 displacement.

      1. I think the CAFE laws have made the automakers stupid, Toyota at least kept the Tundra sane and won’t offer a diesel but are going stupid with hydrogen.

        Trying to squeeze 1mpg out of these 1/2 tons in order to meet CAFE laws and building unreliable expensive diesel variants is a waste resources and success. Electric drive is clearly the future, 10 speeds and diesel is a waste of resourcing, from a modernization perspective this is counterproductive.

        1. Electric drive is only the future if we have enough electricity to meet the demand. Right now we can’t meet the demand electricity they we are producing now.

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