TxTruckMan

Fort Worth

The Discount Tire shop near me is pretty good about buying back older tires kind of like a trade in. So you could go to them and see what a new set of tires would cost you with a trade in of your old tires if you're that interested.

Don't count on it. GM usually applies these types of updates to future vehicles and rarely pushes new features back to older vehicles. This will incentivize you to trade up to a new vehicle.

Hey there everybody. I know this is an older thread but I wanted to share some info I learned on these shocks. I’m at 65,000 miles on my 2021 AT4 and was looking for some shocks to replace my original Ranchos. Somehow I found a brand new full set of ZR2 suspension (GM 85640298) local on FB marketplace for $1800 and couldn’t pass it up. The rear shocks were the same part numbers as listed earlier in this thread - 85599366 & 85599367. But the fronts were different part numbers - 87817370 & 87817371. I installed everything over the weekend without any issues. The rear leaf springs looked to be an inch taller when uninstalled on the ground next to the stock AT4 springs but installed I can’t tell any difference. I suspect they’re softer and eat up the inch under weight. There’s also a replacement bump-stop plate that allows an extra 2-3” of rear travel. I wasn’t expecting that when I picked up the set. The fronts were a little harder to install as all the info I found online said you could install the struts just by disconnecting the UCA. You can’t and also have to disconnect the sway bar and remove the rear brace from the lower CA to R&R the struts. No big deal after I figured it out. I’ve only driven on them for two days on the highway so haven’t really tested out the suspension. I can definitely tell the setup is softer than the stock suspension. I’m probably headed to my hunting lease this weekend so hope to get a better feel them off-road on some rocky/gravel trails. They’re obviously better than my 65k mile Ranchos. I hope this info helps someone else out there.

It’s bad for your engine. Don’t do it regularly. Occasionally is ok.

80 PSI? Wow. I bet that's a rough ride!

I just had this issue pop up about a week or two ago. I have my mirrors set to lower when in Reverse. Of course they go back when switching to Drive. But I just noticed that they now chatter for about 3-5 seconds when they move back. Both sides do this. Anybody else experiencing this issue?

It’s okay to admit when you’re wrong. If every part was built to the same size and spec we’d all be driving the same trucks! You’re the idiot that didn’t do the research before you bought it. Don’t get mad at GM for giving the rest of us different opinions that we want!

Yep. Streaming music from Apple Music is a breeze and sounds great. I never listen to anything else these days.

Yep. Get the seatbelt tight and you will be fine.

I’m not a fan of bed caps. They all look cheap and ugly. Get a cover or nothing at all.

35k miles on mine and no chips at all. I drive lots of dirt roads. I assume it’s because it’s painted plastic instead of hard metal that helps prevent chips. My front bumped has tons of chips. I love the painted wheel arches. It makes the wheel wells appear smaller. Do it. You won’t regret it.

And FYI the GM and Ford 10 speed trans are the same design I believe. Designed by Ford.

My last truck was a Denali with 22’s. The ride was great. I had no complaints. You will barely notice a difference switching to 20’s. The weight is negligible for ride. Only the sidewall makes any difference. The 22’s will handle better while the 20’s will have a very slightly better ride. 22’s look MUCH better. Just watch out for curbs.

I'm pretty sure that it does not have the factory 2" lift. Unless something has changed recently, only the Trail Boss, ZR2, AT4, and AT4X come with the factory lift.