topgear1224

Not really, The biggest issue I have with 3.23s is that it can't stay in 10th gear and it can't even shift into 10th gear until 70 miles an hour. at 70 miles an hour if I lock it in 9th and then change it back to automatic so it engages 10th it's the same MPG on the same road. so there's no point in having that rear gear unless you live somewhere with an 85+ mile an hour speed limit. I maxed out my truck to 15,000 lb GCWR and it was "fine" but the exhaust brake doesn't really help that much, it's better than not having one and freewheeling down the mountain, but it's doesn't work that well when you start moving anything over 7,000 pounds. on a long 6% grade I ended up having to drag my brakes even with manual downshifting and pulling over 4200 RPM. 3.73 is much better in this regards. Are you planning on lifting it? 3.23s already feel undergeared for the 33in stock tire size. I finally got to drive a diesel off-road package and now I'm debating whether or not I want to take the massive depreciation hit and trade my brand new truck that I've had for 4 months in for one. The in gear acceleration goes from being "well at least it's efficient" to "hold up did I just spin in 2nd gear???" I call the 3L "adequate" with the 3.23 but when you have 3.73s it genuinely becomes quick. Also the 3.73 truck really liked to ride it's torque curve versus my truck which tries to ride its torque curve and then downshifts two gears. Fuel economy for 3.73 and 3.23 is exactly the same. You're not going to see a real world difference unless you're setting the cruise control at 90 miles an hour. Sent from my SM-N975U using Tapatalk

Yes it is. If your truck came with 20's the spare tires diameter is the same as your stock tire, it just has a 17-inch rim. Sent from my SM-N975U using Tapatalk

Unless you bought the LT with the diesel off-road package you have 3.23. even the AT4 3.0 gets 3.23 It's a $2,300 option here's what it includes. Sent from my SM-N975U using Tapatalk

There really is no replacement for a steeper gear. People will say "oh you don't really noticed the shallow gears because of the 10 speed" and although it makes it acceptable, If you lock them both in the same gear with the same load you'd be amazed how much better the 3.73 will accelerate. Also you're buying a vehicle that's high torque low horsepower. Why not multiply your strength with that 3.73? and since horsepower is simply torque over time you're going to improve your high-end acceleration as well. Steeper gears also bring the gear spacing closer together meaning you're not going to have to work the truck anywhere near as hard (rpm wise) in day-to-day use. I had no idea the diesel off-road package existed when I purchased my truck otherwise I would have ordered one. Sent from my SM-N975U using Tapatalk

I own the 3.23 version and I can tell you that 3.73 are 100% worth it! GM has programed the vehicle to limit torque in first gear below 3k Rpm. since the spread between first and second is pretty large the vehicle does not like to downshift into first gear so most of your rolling acceleration occurs in second and that's where 3.73 is going to absolutely beat the face in of a 3.23 truck. don't be concerned about fuel economy. it's not going to change at all, in fact with 3.23s at 70 miles an hour (stock 20" all terrain's) is the lowest it can engage 10th gear, there's no gain in fuel economy between 9th and 10th, at that speed, because there is so much load because of the numerically low gears. also if you plan on Towing you're only going to build about 12 to 13 lb of boost when trying to engine brake. The 3.73s are going to make the engine brake much more effective since it's multiplying the negative torque (engine braking). if you do mountains and you don't particularly like manually shifting and you just want to leave it in tow/haul mode you're going to have a much better Towing experience. When I Maxed my truck out (15k GCWR) in order to stop it accelerating down the hills or at least slow the rate at which it tried to accelerate, I had to take manual control the transmission and engage the lowest possible gear. Even then had to drag my brakes down the 6%. Overall other than the brake issue (shitty OEM pads)...... I do enjoy my 2020 GMC Sierra X31 elevation, but if I had to do it again, I would get the Chevy LT with the diesel off road package 1000%. the Chevy has better aerodynamics, much better aftermarket bumper support, and it doesn't have cheap-looking satin-chrome finishes for no reason on the interior. Round Gauges are easier to read as well. if you want to run larger tires and a lift Chevys can do 35s on a 4-inch where is the Sierra has to go all the way up to a six inch and requires a large amount of trimming. 3.73 is are also going to handle a larger tire much better. (Less performance loss) the only use case I could see for not getting a 3.73 gear truck would be if you had a commute everyday in the 85 mile-an-hour zone in Texas, also with the higher gear ratios the g80 engages more predictably. This was very apparent on the V6 3.42 truck that I had as a loner. Sent from my SM-N975U using Tapatalk

So one thing that I knew of but I haven't really talked about is the ECM has the ability to monitor frictional losses inside the engine. For instance my oil temperatures were alarmingly high (330°+) when I first got the truck, they have since settled way down and I believe that was due to increased friction from the break in process. to the best of my knowledge, those same increased frictional losses would cause increased fuel consumption or at least the higher oil temperatures would lead me to believe that the in cylinder temperatures are increased which requires more DEF to be used, since high temperatures create more NoX, DEF controls nox output. This is just a guess, an educated guess, but a guess nevertheless. I'm now approaching 5,000 miles and it still says I have over half a tank remaining. Sent from my SM-N975U using Tapatalk

Requires 20 inch or larger Sent from my SM-N975U using Tapatalk

It does if you just drive it to where the bar actually goes red. On my last fill up I think it said that I was like ten miles to speed limited. It doesn't hurt anything, you're not producing any extra emissions until it actually runs out of DEF. when you get the undismissable reminder that's when you can fit about 5 gallons in. Sent from my SM-N975U using Tapatalk

Yeah it's kind of like fuel gauges. on my 2001 2500HD E means EMPTY!! You about to run out of fuel in 5 to 10 miles!! (Done it twice while towing HEAVY) on this new truck the fuel light doesn't even come on until the gauge is basically sitting on E. I feel like they did the same thing with the DEF gauge. It'll say 1000 miles remaining but then if you go and hook up your trailer and pound on the truck you'll blow through that 1k miles in 150miles. It's trying to predict future usage based on short-term usage and it's really not good at it. the metric is supposed to be DEF per gallon of fuel used. GM really should have just threw that stupid bar graph away, and given us a consumption gauge like they do for fuel but instead change it to DEF and allow us to set it for the last 25 miles, last 50 miles, or the last hundred miles. Deep down inside the ECM it knows exactly how much "reagent" it's injecting. They could have given us an estimated range for the DEF remaining on that same screen. now to be fair if I lived somewhere with DEF at the fuel pump I would just fill up every other fill up and not worry about it. (I avg about 1k-1.5k/month) But since I have to buy it in bottles from Walmart that means I have to wait until I know I can get all 5 gallons in it because I'm not going to roll around and risk it leaking inside of my cab. Sent from my SM-N975U using Tapatalk

I really feel the need to chime in here on the stock brakes, at least on my X31, are complete trash. Sure they'll stop you but you have to give it way too much pedal. And I finally found out why I felt that the brakes weren't really working that well. The ceramic pad material! GM's trying to hit 80,000 miles between brake services.... I managed to overheat them with three 70-40 pull-downs. (At least 1/4 mile in-between each, 55°day, not hitting them hard enough to make the nose dive) On the final one the pads started slipping on the rotor, and the rotors blued. This was with an empty truck! Completely unacceptable from any brake setup, particularly one that has 4 piston front calipers. I should have known just by the fact that GM was offering a $3,500 brake upgrade, that somebody in the engineering team knew that the brakes weren't good enough. Don't get me started on around town when slowing to a stop light. The engine, even with my foot completely off the gas fights the brakes. I found the only way it's come to a smooth stop or at least stop where I want to is to knock it into neutral. Sent from my SM-N975U using Tapatalk

What pads do they use? Sent from my SM-N975U using Tapatalk

My X31 full droops on the highway over bigger bumps.... I know there's some level kits that are 1 inch lower spacer and a 1 inch upper spacer for the strut. Sent from my SM-N975U using Tapatalk

Those would be dealer discounts not the nearly 11k GM put on the hood of 2020's. Sent from my SM-N975U using Tapatalk

Some of the trucks have "bad" gauges and it will suddenly plummet to half. I've noticed that it's more RPM dependent then load (although the metric is DEF per gallon of fuel used) for instance when I have it in off-road mode and I'm running the dirt roads a lot with rail to the high RPM going up the hills it will say it's using a ton of d e f I'll know on the next fill-up what my actual average is since I only put in 5 gallons. Mine was completely empty at 2771. 4646 now and it's over half full. Sent from my SM-N975U using Tapatalk

Ya I was down until they said that if you do 0% for 84 you have to pay MSRP. Which in my case was $10k more.... Can't get any discounts if you do the deal. Sent from my SM-N975U using Tapatalk

Interesting, I saw in their own truck the gap. I still don't believe that is the clunk, but maybe it is loading torsionally and that is making it bind then release in the joint. Kinda like how bad CV angles create vibration at highway speeds in 4hi on 01-06 2500hd trucks. Sent from my SM-N975U using Tapatalk

What I found is it really depends on what you're driven and what you've not driven for instance for me although I recognize that a linear spring is much more predictable I actually prefer a variable rate spring such as a dual rate or, in Chevy's history, a torsion bar. a lot of people said the 2019 trucks are jiggly and this is true at 30 miles an hour I definitely felt a little jiggle even on a non Max tow truck but here in Alaska with a lot of random dips at highway speeds and Crest and double bumps, don't forget frost heaves. The ride is extraordinary well-controlled on the base 4X4. in contrast my X31 is incredibly smooth at 30 miles an hour, no juggle whatsoever, however at 60 to 70 miles an hour over those same bumps the suspension bottoms out or overextends. I also feel the need to point out that the 2019 AT4 and Trail Boss suspension is different then the 2020 version. The shocks are tuned differently to allow more medium to high speed trail running. GM made this change directly in response to Media feedback that the back end was too Skippy on washboards with the 2019 model. I suppose I should just go to a dealer and drive a Trail Boss model and I'll know since I commute on roads near the dealership what the actual difference is. Sent from my SM-N975U using Tapatalk

Looks a bit nose high, I'm sure it isn't, just looks that way. Love the look though. Was it a spacer in addition to the GM lift? How did the ride quality change going from a Z71 to the Trail Boss suspension? Like in what ways is it different. Sent from my SM-N975U using Tapatalk

You think you limited.... Serria need a 6 inch lift AND trimming to do a 35.... You can do 37 with the same lift kit. My stock size is 33", up until 6 inch kits that's as large as I can go. (Can't trim due to the gunk they throw on the road and the uncoated frame) Sent from my SM-N975U using Tapatalk

84768245 doesn't exist in any system I've seen, this is the first time I've heard of a kit for the composite trucks. Sent from my SM-N975U using Tapatalk

The "trail boss kit" includes Monotube rancho shocks. (All others other than AT4 and Trail Boss use an inferior twin tube design from factory) the whole truck goes up by approximately 2in in the front and IIRC 1.75in in the rear. the kit includes, when installed at a dealer, a recalibration for the electronic power steering system (that way you don't harm the system at full lock) others that have had it installed also say it includes a reprogramming of the speedo for a corrected tire size if you choose to go bigger wheels and tires. (Yet to seen any official documentation of this) Longer CV axles are included as well. Sent from my SM-N975U using Tapatalk

2019+ Chevrolet Silverado 1500 equipped with composite rear leaf springs: 1. Chevrolet LT Trim with 5.3L V8 engine (L84) 2. Chevrolet LT Trim, Short Bed, with 3.0L engine (LM2) Sent from my SM-N975U using Tapatalk

Yes that kit will turn you into a trail boss. What engine does your LT have? Sent from my SM-N975U using Tapatalk

But to answer your question more directly air dynamics will definitely take a hit, fuel mileage will go down. With it not smoothing that transition the air is going to swirl behind the bumper and that's going to create front lift and is also going to increase drag and turbulence underneath the vehicle. the air dam effectively creates a negative pressure area where it ends which helps siphon heat out. That being said unless you're working the truck to the absolute limit of its OE cooling package's capabilities, it is unlikely you're going to have any ill effects such as overheating. Since you have electric fans. I would however be concerned about road debris possibly getting kicked up from that turbulent air and causing damage to the fins on the cooling package though. Sent from my SM-N975U using Tapatalk

I could have sworn it was in the owner's manual on how to remove the lower air dam. but looking at your picture I'm starting to think that the AT4 comes with it shaved off already. Sent from my SM-N975U using Tapatalk