20' AT4 to 21' AT4 what I noticed in the change

[todd308]

I suppose I thought it was just interesting to document what I've noticed that has been different in my change from a 20' to 21' AT4.    Long story short I did the swap and came out a few grand ahead in the deal with the crazy high used prices and finding a dealer that would still deal on a 21'

 

Anyway I thought it was interesting to note some of the differences I've noticed.   Now both of these are the exact same trim, except that I went from 20" wheels with the Bridgestone AT highway tires to the 18" Goodyear Duratracks.   I'm kind of curious if it's a 20' to 21' thing, or if it's simply sample variation across the model.   Both were assembled in Mexico.  Most of them are minor, not disappointed in the switch at all, but just things I noticed right away over the first couple weeks. 

 

First, the "leather" was nicer in my 20', particularly on the steering wheel, 21' steering wheel feels harder more plastic'ish.  Seats seem about the same, but perhaps the leather is not quite as tight.   I also didn't realize how much the seats in my 20' had broke in over the last year, the 21' are quite stiff again.   Also even though I've been very careful cleaning/conditioning the seats in my 20' not putting too much conditioner on them for the air ports and cleaning them with a horsehair brush, they've either clogged up a lot over a year or never worked great, the ventilated seats on the 21' flow much better.

 

Second totally different tires/wheels, but I've driven lots of cars/trucks with all ranges of tires, but the 18" rims and duratracs are a huge difference in handling and noise.   They have a ton of vibration at various speeds, and it almost sounds like a vehicle locked in 4hi with transfer case whine speeding up/slowing down.  You can feel the tire vibration through the wheel, it's subtle but coming from the very smooth 20' bridgestones it's super noticeable. Also the side to side handling is really slow/mushy compared to the 20's.   Again I've driven some pretty aggressive AT tires, and they were still more quiet/smooth than the duratracs.   The mush in the sidewall reminds me of the old second gen Yokohama Geolanders.   I'm running them at the recommended PSI so perhaps they need a bit more.   You can also definitely feel the extra 60+lbs of extra tire weight slowing down and speeding up.  Also since the 18" wheels and duratracks are almost 1" smaller diameter than the 20" wheels, the truck of course sits 1/2" lower and loses 1/2" of ground clearance.   

 

Love the look of the high clearance steps, but not the function.  The older steps were much better as an actual step.  These are of course much better clearance and they look great, but they put you almost too high so you have a bigger step to the running board, but then have to duck into the truck.   It might almost be easier to get in/out without them on at all. 

 

Rear bed liner was sprayed nicer/ more consistent in my 20'.   My 21' isn't bad but you can see where they didn't apply it as consistently/thickly in corners and at seams. 

 

The HUD has a bit of "double vision"  at the very bottom it's like it's a bit out of focus, the rest of the screen is crisp.   Also not sure why but it seems the interior reflections on the side and windshield from inside the vehicle are worse on the 21' than my 20'   The dash reflection onto the windshield is stronger, and for example the side driving mode/light knobs reflect in the drivers side window where you look at the side mirror and I never noticed any reflections there in my 20'

 

GMC did away with the smaller 1" bottom trim on the "mall skirt" front lower fairing.  Don't miss it, but several people have reported that without it the middle section of the upper wide fairing sags over time.

 

My 20' was WAY more rusted underneath when I got it, especially at the CV joints, and also the UCA's on my 20' looked like they were dipped in a salt bath.  21' is much cleaner underneath, undercoating seems better applied. 

 

Also I noticed that somewhere along the line in my 20' the drivers side wiper stopped wiping cleanly.  It would leave streaks right where the wiper arm attached.  Tried 2-3 different wiper blades including stock replacements, didn't help.  Never did it when new.   The new truck, wipes perfect with either factory or bosh blades.   I had another post on this and others had solved the issue by replacing the arm the wiper blade attaches to, the theory being it gets bent easily, for example in winter with heavy snow.  I never did replace mine to see, but it will be interesting to see if this pops up again after winter in the new truck.

 

The exhaust on the 21' seems to have more rumble/throat to it than my 20' did, neither had the performance package, so they should have been the same.  I haven't crawled under it to see if anything looks different. 

 

Autostart from a stop seems faster on the 21', in my 20' I could pretty easily get from the brake to the gas before the truck was started and ready to go to the point it would get annoying at lights, the 21' it's fast enough I have yet to find myself waiting for it when a light turns green.

 

Just to add some more things I've noticed:

 

Seat leather was much tighter in my 20', after only 2 months my 21' seats look more loose in places than my 20' did after a year.

 

My 20' when it rained, frequently had issues with the parking sensors not working, or they would indicate stuff right in front of me vibrating the seat at stop lights/signs, it also disabled the adaptive cruise a lot in rain/low sun etc.  I have not noticed either issue in my 21' so far.  The dealer of course said it was "normal operation"

 

My 20' had voice recognition worthy of the 1970's technology, it could never understand "Home Depot"  "Costco" etc. when trying to navigate.  My 21' seems to do a much better job with voice recognition.  Still horrible compared to say using Apple Carplay, but way better than my 20' was. 

Edited June 23, 2021 by todd308

[Rackumrack]

Nice write up. I thought of selling my 2020 AT4 for the KBB cash price and sitting on the equity and waiting for the new model year 2022 to be released in 2024 . I am interested in the interior upgrades of the '22.  With that said I really have no problems with the truck beit only having 13,000 miles and them no longer offering pacific blue in the AT4 trim. What color did you have and what do you have now?

[todd308]

I had the Dark Sky Blue and went to the Satin Steel Gray.

 

I had a love/hate relationship with the Dark Sky Blue, in the right sun it looks absolutely amazing, but most of the time it just looked like a very boring dark blue/gray.    Also being so dark it really showed dirt.   The Satin Steel to me looks better in a wider variety of light, and it looks cleaner.   But man on a bright day at the right angle the Dark Sky was something.

[todd308]

I'd also add that another gremlin appears to have shown up that was never an issue in my 20' 

 

I have the setting set that will auto-lock the doors if you walk away from the truck.  On my 20' it did this for a year without issue.  On my 21' I'd say every 4-5 times it won't lock.     When this happens I've even tried manually locking the doors with the keyfob and they will not lock.  It's like the truck is convinced that the key fob is still in the truck so it won't lock.