2019 Transmission and Axle Ratios

HondaHawkGT · June 19, 2018

Here's the latest from the 2019 order guide.

Here's a quick comparison of the final drive ratio of a few different transmission and axles

2019 Standard Transmission & Axle

The 8L90+3.23 replaces the 6L80+3.42

The 10L80/90+3.23 replaces the 8L90+3.23

I added the 6L80+3.73 as an additional reference.

2019 Max Trailering Packages

The 8L90+3.42 replaces the 6L80+3.73 / Carries over for 2019 from the 2018 Silverado LTZ/Sierra SLT CCSB 5.3 + 8-speed + 3.42 Max Tow Package

The 10L80/90+3.42 replaces the 8L90+3.42 for the 6.2L.

The Max Trailering Package (GU6) is a 9.76" axle on LT and RST trims when equipped with Z82, G80, and 18" or 20" wheels. IBC is included.

I added the 6L80+4.10 as an additional reference.

2018 Silverado/Sierra 6.2 vs 2019 Silverado/Sierra 6.2

If there's anything wrong let me know and I can fix it. Just trying to put the information out there to help people see how the 2019 drivetrain options compare. Interesting to note that the order guide seems to suggest that all 3.42 axles paired with either the 8-speed or 10-speed will be 9.76" regardless of whether you have the 5.3 L84 or 6.2 L87. I'm assuming (not 100% positive) that the standard 3.23 axle ratio will also be a 9.76" axle. Important information to consider for those that might regear their truck since R&P's for the 9.76" axle are still limited.

Edited June 20, 2018 by HondaHawkGT

Grumpy Bear · June 20, 2018

Whew! I'm dizzy.

ExFordGuy77 · June 20, 2018

I thought the 6 speed and 3.42's was decent but the 8 and 10 speed transmissions are really game changers. I never bothered with test driving the 8 speed trucks so far just because it was so rare outside of the crew cab with the mini box. I cant wait to see how peppy the 2019 trucks will be. Up to 450 lbs lighter and even the "tall" 3.23's are close to the same thing as the 6 speed with 3.73's. To me it seems like GM got the gear ratios right. No more 3.08 slugs and the 3.23's should pull strong and still cruise at 70 with great fuel economy. I can't wait to see how the 6.2 performs in a lighter truck and the 10 speed with 3.42's. It'll be a monster showdown between the 3.5 ecoboost and 6.2 with both having the 10 speed.

HondaHawkGT · June 20, 2018

The 6.2 + 10-speed + 3.42's is going to be a rocket. 400 or so pounds lighter, and all the gearing it could ever need. It might not win top spot in TFLT's Ike Gauntlet, but for us closer to sea level, the truck should be a beast.

Now that the 5.3 isn't stuck with the 6L80, it has a much better chance at showing what it can do. I've been impressed with the Gen V 5.3 in my truck, hopefully GM gives the 8-speed a tune that can make it shine. The axle ratios look solid like you brought up. It's like GM made the 6L80 and 3.73's the minimum for the 5.3 and the 8L90+3.42's are close pretty much the equivalent of the 6L80+4.10's, which is nuts.

Big_D · June 20, 2018

Now if only I can get an AT4/6.2 with the max trailer pack. Would like some 3.42s and tow mirrors in that trim.

ChuckTuna · June 27, 2018

Which transmission and axle ratio should I get if I want to lift it and put 35" tires on it (without changing the axle ratio)? I'm assuming these calculations are with standard tire sizes.

Thanks

shift_grind · June 27, 2018

You'd want the max tow package. Hope you didn't want a Trailboss, Elevation or even a Z71 truck.

ExFordGuy77 · June 30, 2018

On 6/26/2018 at 7:03 PM, ChuckTuna said:

Which transmission and axle ratio should I get if I want to lift it and put 35" tires on it (without changing the axle ratio)? I'm assuming these calculations are with standard tire sizes.

Thanks

If you want a Trailboss or Z71, you'll get the 8-speed and 3.23's. If you don't want a Z71 or Trailboss, you can get 3.42's in the max tow package. Either gear set will be fine with the 8-speed. If you take a look at the 2014-18 section, most guys with K2 trucks running 35's usually recommend 3.73's or 4.10's. The 8sp with 3.23's has better gearing than the 6 speed with 3.73's in every gear other than 1st, amd even 1st is really close. It's actually kind of close to the 6sp and 4.10's in 2nd 3rd 4th. That's the benefit of using the transmission to do the gear reduction, axle ratio isn't a big deal. I would go with 3.23's just to get the Z71 package and 2 speed transfer case. The 8 speed will have no problem turning 35's. The Hall Racing ZR2 that races in the Best in the Desert series runs 35" tires using the factory 8speed, 3.42's, and the 3.6 V6. It has no problem racing through the desert. With that setup.

ChuckTuna · June 30, 2018

2 hours ago, ExFordGuy77 said:

If you want a Trailboss or Z71, you'll get the 8-speed and 3.23's. If you don't want a Z71 or Trailboss, you can get 3.42's in the max tow package. Either gear set will be fine with the 8-speed. If you take a look at the 2014-18 section, most guys with K2 trucks running 35's usually recommend 3.73's or 4.10's. The 8sp with 3.23's has better gearing than the 6 speed with 3.73's in every gear other than 1st, amd even 1st is really close. It's actually kind of close to the 6sp and 4.10's in 2nd 3rd 4th. That's the benefit of using the transmission to do the gear reduction, axle ratio isn't a big deal. I would go with 3.23's just to get the Z71 package and 2 speed transfer case. The 8 speed will have no problem turning 35's. The Hall Racing ZR2 that races in the Best in the Desert series runs 35" tires using the factory 8speed, 3.42's, and the 3.6 V6. It has no problem racing through the desert. With that setup.

Based on the following chart I assume you mean the LT Trailboss correct? Since it doesn't appear the Custom Trailboss comes with an 8 speed.

In my case I probably won't consider any of the high priced models (LT TB, LTZ, and High Country). I do not want leather seats which I believe takes the RST off the table (at least I think they are standard with leather seats unless I am mistaken). Since the WT, Custom, and Custom Trailboss aren't offered with 8 speed transmissions I believe the LT would be the best choice for me.

I think in my case I will have to look for an 2wd LT (all-star edition for g80) w/ the 5.3L V8 or the Diesel and in your opinion either with 3.23 should be fine if I wanted to put 35" tires and a lift or just get the Max towing option and have the 3.42?

Thanks for your advice.

Edited June 30, 2018 by ChuckTuna

shift_grind · July 2, 2018

I believe only the LTZ and High Country come with leather standard.

If you want 35s, you should shoot for the Max Tow option. It's not just the diameter and effective gear ratio change but also the weight of the tire. 35s are very heavy.

Edited July 2, 2018 by shift_grind

newdude · July 2, 2018

Huh. I just noticed that WT-Custom TB that use the updated old engines (LV3/L82/MYC) only have 3.42 gears 2WD or 4WD. Interesting.

ChuckTuna · July 3, 2018

On 7/1/2018 at 7:15 PM, shift_grind said:

I believe only the LTZ and High Country come with leather standard.

If you want 35s, you should shoot for the Max Tow option. It's not just the diameter and effective gear ratio change but also the weight of the tire. 35s are very heavy.

Ah, I thought the RST pictures were leather but if you think it's still only the LTZ and HC, I'll take your word for it. If the RST is on the table I would have to check if getting the G80 is an option. I basically figured out that the all Star edition covers all the bases required to get NHT without the Z71 deal breaker.

I have decided to hold off on buying until next year, partly because I will be in a better financial position but more because I think the '19 model is more practical and I am more confident in what I should be buying the All star NHT LT without having to play the RPO shuffle at the dealer for a current '18 model. I also want to read customer reviews about the truck before I buy it. If I have to wait two years.. it will be tough but I might be able to last.

Thanks again for the insight

shift_grind · July 3, 2018

Check out Gmfleetorderguide.com. Click on Chevrolet and then select all new 2019 Silverado from the drop down on the top right. It's not super intuative but it shows you how you can option out the trucks. Subject to change, but it usually doesn't change much if it all.

ChuckTuna · July 3, 2018

I believe that is the site I was using to determine what I needed for the LT to have 3.42 ratio. Last night when I posted about the RST, I did not have access to my computer which is helpful as Ctrl + f can help navigate more easily (I don't even want to bother trying it with my phone). I was able to determine that the RST is capable of having the All-star package although (not 100% sure about this) I think it requires the truck to have bucket seats unless I misunderstood the sidenote.

While I wouldn't consider that a deal breaker, I don't mind the bench seat either.

HondaHawkGT · July 6, 2018

On 6/30/2018 at 6:31 PM, ChuckTuna said:

I think in my case I will have to look for an 2wd LT (all-star edition for g80) w/ the 5.3L V8 or the Diesel and in your opinion either with 3.23 should be fine if I wanted to put 35" tires and a lift or just get the Max towing option and have the 3.42?

For 35's, most guys driving K2 (14-18 trucks) recommend at least 3.73's if you have a 6 speed transmission. A 2019 truck with the 5.3, 8 speed, and 3.23's has better gearing than the 6-speed with 3.73's and comes close to the gearing advantage of the 6-speed with 4.10's. It will have no issue with 35's for 99% of the population.

Edited July 6, 2018 by HondaHawkGT