I installed the illuminated black emblem on my '21 AT4 today. The write up here was great (thanks!) to know what I was in for. I'll add a few comments from my install experience:
I'll post a picture tonight after it gets dark.
- 90% of the job is getting the old emblems off without damaging the grill. They're attached much stronger than I anticipated. Plan to get frustrated and cuss.
- I was doing this solo. A second set of hands would've made things much easier, namely with the removal of the existing emblems. Unless you're willing to pop the top of the front bumper off their retainers, you can barely fit your wrist behind the grill - let alone a decent sized screwdriver... and still be able to see what you're doing. You almost need 1 person pulling the top of the grill to make room, while another person is working to unfasten the emblem clips.
- My man card may be revoked for admitting this, but after an hour of trying the emblem removal approach laid out by the OP, I gave in and switched to following the GM instructions for removing them. This involved taking a small flat blade screwdriver and popping the red GMC inserts out of the 3 chrome letters. Once the red inserts are removed, ALL of the retaining clips for the chrome emblems are directly and EASILY accessible from the front; no back side access needed. In fact, using this approach, you don't even need to loosen up the grill (the 6 screws as laid out by the OP). Simply pry out the red insets, then use a flat blade directly against the emblem retaining clips (which are a PITA to release from the backside). After switching approaches, I literally had all 3 letters removed in < 15 minutes. Versus an hour+ of cussing, bruised and cut wrist/fingers, etc. with nothing to show for it. Downside? Your OEM emblem is basically garbage - it's still functional but dinged and scraped. IMHO, not a big deal as I don't ever plan on pulling the new illuminated one off. And if need be, you can always by a new standard one.
- It took me about 2.5 hours start to finish, not including the hour wasted on backside emblem removal. That includes final screw torqueing to spec, testing and cleaning all parts and surfaces before reassembly. Could probably do it in 90 minutes if you're just ripping and replacing, and backyard mechanic'ing it.
- When buying the part from the GMC Accessories website, it offered dealer installation as an add on at checkout. Different dealers had different prices. I had one by me offering install for $65 which was almost to cheap to believe. But if you're debating on DIY vs. paying the dealer, you should certainly check out several of the dealers on the checkout screen for pricing, as I saw ranges of $65-200. $65 looks like a heck of a deal after doing mine, but I also wanted the satisfaction of knowing mine was done right (DIY).
- GMC install instructions are here if you need them: https://ecom-dam.ext.gm.com/parts/documents/ISheets_84435780.pdf