DSW1519

I did the same thing as AJMBLAZER did (two posts above). My rear slider was leaking the first week I had the truck in December 2020. Dealer performed the TSB back then. Within a few weeks it started leaking again. I also sealed the top of the window (completely filling the channel). To date still no leaks. Easy to do and good results.

Sorry for the delay in responding as I just saw this post. Dealer had the truck for 3 weeks total due to parts delays. So far the truck is good.

God for you and I hope your good luck continues. I've had my 21 SLT since December 4th. So far windshield has been replaced, rear window leak, lifters replaced and the battery has been replaced. All under warranty, but doesn't bode well for durability and dependability. I do love the truck but hate having so many issues. Good luck to you with yours and I truly hope you don't have any issues. .

Just got my truck back. 21 SLT 5.3 10 spd, 7500 miles. Had a faulty lifer on 7/16. They replaced all 16 lifters. Hopefully this is solved, but I'm concerned about future failures.

Dealer just called. Lifter failure. Truck is a 21 5.3 10 spd with 7500 miles. They are going to replace all 16 lifters. No ETA yet on when the parts will be available. Totally pathetic.

2021 SLT 5.3 10 spd. Built 11/2020. 7500 miles on it. Dealer just called and have a faulty lifter. Dealer says they will replace all 16 lifters, but no eta on parts yet. I don't driveit hard, so it sucks that they have to tear into the engine with so little use.

I have the same isue as Bruce Stein above. 21 SLT 5.3 10 spd 7700 miles. This morning while driving first heard the engine noise - between a tap and a knock. Then rough idling. Then the Inst Panel went nuts displaying service ESC and other messages. Luckily I was only 2 miles from home. Having GM Roadside Assist come and get it. It sounds like I have the same sysmptons as others have mentioned in this tread. I'm assuming either a lifter or valve spring issue. Called dealer and they can't look at it until Monday. They also won't have a loaner for me until Monday. I will post updates in this thread as I move along with this issue.

I love the look of the AT4, especially the exterior, but I ordered and bought a 21 SLT with the premium plus. I don't use a truck off road, other than the beach occasionally. The biggest reason for this for me was I didn't want the off road tires and off road suspension package. I was looking for the quieter and smoother ride, so that is what made the decision for me to go with the SLT. No regrets and love the truck.

See my post on 3/4/21 in this tread. Sent from my Pixel 3a XL using Tapatalk

GN2018 - I truly understand your concerns and was in your position last fall. I ordered a 21 and took delivery in December 2020. I ordered the truck being aware of the leaking slider issue, and because I liked the truck so much (and despised my 18 F150 so much) that it was worth the gamble. I also decided that if the slider became a continued issue I would pay the cost of swapping for a non-sliding window - and knew that was a possibility from the start. Ten days into ownership the rear slider started leaking. Dealer performed the TSB and sealed the slider top gap. It was good until mid February, where I notice a slight drip after days of rain. It was a small enough leak that the towel I have on the rear seat back wasn't wet to the touch. Once we had a warm day I put a layer of flowable silicone on the top of the window gap - see my post in this thread on 3/4/20 with details. We've had numerous days of rain since then with no leaks so far. As mentioned above if this continues to be a problem I'm going the solid window swap route, and will pay the cost out of pocket. For me I love the truck. The hassle of dealing with this, while not ideal and really pathetic, is worth it as overall I'm really happy with the truck. I wouldn't own another Ford due to the numerous issues I had with my 2018 F150. I feel like my GMC is superior in just about every way. As mentioned elsewhere in this thread it seems Ford and RAM trucks also have leaking sliders on some models. IMO the real issue is the crappy plastic window frames are mostly to blame. This is just my 2cents, and I hope this helps you.

I agree with what you are saying. Where the drip on the inside was located that is the lowest point, so I'm not exactly sure where the actual leak was coming from other than knowing it was somewhere along the top of the window frame. That is why I made multiple passes along the entire top of the window frame. This is why this thin runny silicone seems to be the solution. Sent from my Pixel 3a XL using Tapatalk

X2. Sent from my SM-T290 using Tapatalk

No problem. Dave the service manager is a really good guy. Sent from my Pixel 3a XL using Tapatalk

I had the TSB done at O'Neil GMC in Warminster. They used an outside glass specialist and they did a good job. I can't even tell the truck had been touched. I bought this truck at O'Neil, and I'm very happy with how they've treated me - both in sales and service. I attribute the slight leak (after the TSB) to the crappy window frame design.

TSB Sealing Repair Completed – UPDATE Quick background – Picked up my ’21 Sierra on 12/4/20. Within 10 days of ownership I had the leak on both sides at the top of the slider. Dealer completed the TSB, and I could see a heavy bead of the sealer that was laid across the top frame of the slider. After the TSB was done I didn’t see any leaks and continue to check very closely after every rain. I have a small towel sitting on top of the rear seat back rest just in case the slider starts leaking again. About a month ago during a steady rain I saw a drop of water from the same location - literally a few drips where it was barely leaking, but the towel on the seat back rest was dry to the touch as was the carpeting. As others in this thread have suggested and since it was barely leaking I decided to try the flowable silicone (permatex 81730) rather than have the truck torn apart again. When we had a warm day I cleaned the top of the slider as best I could and also taped off the top of the glass on the slider to try and minimize the mess. I used a full tube of the permatex and made a few passes across the top of the slider frame, being careful to not overfill the area. As other posters have mentioned that have used this product it is thin and runny, so being careful minimizes the clean up. Since using the flowable silicone 4 weeks ago we have had both snow and rain. Over the past week we have had significant rain, including long periods of drizzle, solid rain and heavy down pours. So far no leaks, so the effort was well worth it. I can see along the top of the slider frame where the flowable silicone has dried there is an even layer of silicone across the complete gap. It looks like the permatex product took care of any small gaps that the TSB work didn't completely seal. So far I’m really impressed with the permatex product and will use it again should I see a small leak in the future. Pic below of where it was leaking and also of the permatex product used. Thanks to everyone that recommended this product and the idea.