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    '21 Silverado LT 5.3 CCSB 4x4

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voided3's Achievements


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  1. Our '21 Silverado 5.3 8-speed hasn't done the cold 1-2 rough shift in a while, but it has multiple times before. I got in the habit of holding it in neutral for a few seconds between reverse and drive, and that seems to prevent it. I also always let it warm up for a minute or two before leaving (until the tachometer goes down to a normal idle speed, around 600 RPM). This warm up procedure is generally a good practice for any vehicle on a cold start, really.
  2. Thanks for sharing this! I can't believe they placed that braided ground strap directly behind the front wheel like that. They should have mounted it higher up on the frame behind the fender well liner to protect it at least. The strap on our garage-kept '21 is looking just fine, but I just coated it with Fluid Film as a preventative measure.
  3. Yeah, that's what has kept me from doing anything that could be considered a modification on our truck. We had lifter failure on ours at 585 miles and got an extended component coverage letter for the engine and related components, after the back and forth hassle of getting that addressed over a few months, so I decided to stick with the "L7 method". The other factor is we'd like to replace the truck with a gas 3/4 ton within the next year (if possible, given the current market) as A) we may upsize our travel trailer, B) the GM and Ford HD trucks don't have cylinder deactivation, and C) I've been really unimpressed with the build quality/ownership experience on this particular truck (the lifters weren't the only issue) and I feel keeping it past the warranty period would be a bad financial move.
  4. I can tell L7 disables DFM on our '21 Silverado 5.3 with the 8-speed, especially at low speeds, and I always drive in L7 unless I need to go 75 MPH or faster (which is rare around around here; our local highways only go up to 65 MPH speed limits). With that said, the shifts can still be clunky often due to the shift programming and probably other physical design factors of the 8L90 transmission, but I can tell by watching the tachometer that it isn't locking and unlocking the torque converter nearly as much in L7 as with DFM enabled in D. I've adapted my driving style to avoid the clunks, including holding it in neutral shifting between reverse and drive for at least two seconds, but inevitably it'll still act clunky when letting off the throttle to coast or sometimes when coming to a complete stop, for example. It almost feels like a faulty motor mount or loose torque converter bolts, but unless it throws a code or can't move under its own power, I know it'll be a "cannot duplicate" or "operating as designed" diagnosis at the dealer. It's not GM's finest work, that's for sure.
  5. Our '21 Silverado with the L84 5.3 had the flashing CEL come on four times due to failing lifters on cylinder #6 and #8, though the misfire codes were only coming from cylinder #8. After replacing the lifters, the issue hasn't come back.
  6. I can't speak to how much dust is normal, but we had belt dust buildup on our engine and a belt chirp when cold for the first few minutes. They replaced the serpentine belt, AC belt, and idler pulley at 6300 miles. The truck is now at about 13,500 miles and it hasn't come back yet, and it's hard to tell if the dust currently on the engine is from the original belt or the new one since they unfortunately didn't detail my engine bay for me (haha). I'd just go ahead and have them replace the belt and idler pulley under warranty if they are offering to do it.
  7. Our dealer's service manager facilitated getting a component coverage letter (not the same as an extended powertrain warranty) for just the engine in our truck after getting the lifters replaced on our '21 Silverado. It came in the mail a month after the final repair from the Chevrolet Division of the GM Customer Assistance Center. It effectively gives us 6 years/100,000 mile coverage on the engine, tied to the VIN number of our truck, from the date specified post-repair, but doesn't include any other drivetrain items like the transmission or transfer case; those are still under the original 5 year/60,000 mile powertrain warranty.
  8. The oil change interval won't guarantee much on a relatively new vehicle, but that's good that all 16 were replaced. My rule of thumb is never let the oil life monitor go below 50%, which usually works out to about 3500-4000 miles. In the manual, the "severe service" oil change interval is roughly 4000 miles, anyway, and most manufacturers include short trips and winter driving as "severe service" so basically everyone qualifies.
  9. Honestly, as an owner of a '21 Silverado with the 5.3, I would not buy that truck. There is a reason it's already on the used lot and it's not just because of inflated trade-in values. Even if it came with full lifetime, no questions asked warranty coverage, knowing what I know now about the L84 5.3 V8 and the quality issues GM is currently having, I would never have bought it. Our lifters failed at 585 miles, among other issues. Between repairs and regular maintenance, I've had nine service appointments over 16 months of ownership, four rental cars, and it spent 51 days at the dealer. I sincerely hope this isn't typical for everyone who owns these trucks, but this is not an isolated instance for this particular model year. We plan on trading in ours within the next several months, as well.
  10. The payload rating will be more of the concern with a travel trailer as they tend to lean closer to 15% tongue weight rather than the usual 10%. We tow a smaller 4000 lbs. GVWR camper and with the weight of propane, the power tongue jack, the deep cycle battery, and our hitching equipment on the front of the trailer, our tongue weight is right around 600 lbs. If your trailer loaded is around 6800 lbs., that means you could potentially have up to 1020 lbs. of tongue weight, meaning you would be left with 380 lbs. of payload in the truck for passengers and cargo, if you have 1400 lbs. of payload. If your trailer has a more conservative 12% tongue weight, though (as an example), you would be at 816 lbs. of tongue weight and you get back almost 200 lbs. of payload in the truck. If possible, I would hitch it up loaded and go to a weigh station to see what your axle weights are. That could also influence how you adjust your weight distribution hitch and where you place cargo both in the truck and trailer. If you usually travel with water on board, don't forget to fill that up, too, as water is 8 lbs. per gallon and adds up quick.
  11. Our '21 Silverado with L84 5.3 got the first flashing check engine light at 585 miles. The dealer replaced the lifters only on cylinders #6 and #8 after several visits (the light came back four times in total) around 1800 miles. The truck is now at about 12,500 miles and the issue hasn't come back yet, but 1) I change the oil every 3,000 miles as a preventative measure, and 2) I exclusively drive the truck in L7 on the 8-speed to disable DFM. Despite these measures, I wouldn't be surprised if it happened again given only four out of 16 lifters were replaced. I've mentioned this in other DFM lifter threads, too, but if they remove your serpentine belt for any reason as part of the repair, have them replace it. Ours started failing at 6300 miles because they took it off twice and stretch fit belts are one-time use. They replaced the serpentine belt, AC belt, and idler pulley on ours under warranty. Also make sure they clip your heater hoses back into place. They didn't on ours and I had to clip one back in its retainer so it wouldn't rub on the frame and squeak going over bumps. Even without the manufacturing defect that affected our batch of engines, the lifters will most likely fail between 60,000 and 80,000 miles under normal use, anyway, due to the poor design. If you are not leasing the truck, I would plan on trading it before the 5 year/60,000 mile powertrain warranty is up or get an extended warranty if you hope to keep it longer. We negotiated an extended component coverage (6 years/100,000 miles) letter for the engine on ours that's tied to the VIN number due to the terrible, dragged out repair experience we had with ours over the course of a few months. It's at minimum a $5,000 job out of warranty to get the lifters replaced at the dealer, and if it takes out the whole engine due to metal debris recirculating, it can be as much as $11,000-12,000 for a new engine. With all of that said, we plan on trading in the truck later this year. We use it to tow a modestly sized 4,000 lbs. GVWR camper and I can't deal with a practically brand new truck randomly failing in the middle of nowhere hours from home. No amount of warranty coverage will make you any less screwed in that scenario.
  12. Yeah, it hasn't been a good experience at all. It was the right truck for us on paper, but man did the execution fall short. I drove my parents' '03 Chevy Avalanche a few months ago for the last time, prior to them selling it recently, to compare. Even at almost 20 years old and 170k+ miles with all original drivetrain components, that thing still shifts buttery smooth, rides great (it's a coil sprung Suburban chassis so not apples to apples), runs strong, really comfortable seats, and great forward visibility. It's just night and day to our truck in every aspect and it's super depressing. I'd gladly take 70 less horsepower and four less gears if our truck could drive like that. Side note, our bed it was so crooked they had to remove the plastic locator pin to get it to line up so the dealer's body shop had to do it, otherwise I would have done the same.
  13. Yeah, it's hard to get accurate numbers without hacking into GM's dealer network probably (haha). I figured it would be worth a shot, though, as ours failed so early at 585 miles and I've been curious.
  14. To summarize, the engine has been apart twice for lifter failure (before they finally figured it out), the idler pulley and serpentine belt prematurely failed at 6300 miles, the bed was incorrectly installed crooked at the factory, and the front seats had to be removed to fix incorrectly installed/non-functioning HVAC ducting to the rear. I also have to hold it in neutral for three seconds between reverse and drive or it slams into 2nd gear on the first 1-2 shift of the day. After each repair, the dealer also messed up something and I had to fix it myself: They didn't clip a heater hose back into place so it would rub on the frame going over bumps and squeak, the body shop bent the plastic deflector in front of the passenger side rear wheel so I had them send me the part to install myself, and they didn't reconnect the wiring harness for the rear seat USB ports after removing the front seats so I had to pop the bezel off and reconnect it. They also put over 500 miles on the truck test driving it across the four service appointments for the lifters and burned half a tank of gas without refueling it on the last appointment and never reimbursed me after providing a receipt. They also ran over my floor mats at some point; the front passenger side mat had a distinct Michelin Primacy tread print in it I had to scrub off with a drill brush.... In conclusion, there are some days I hope this piece of $#!^ catches fire on the side of the road and puts itself out of my misery. I might call the fire department to come put it out after a half hour or so, just to be safe.
  15. Lifter failure on the T1-platform trucks and SUVs with the DFM-equipped L84 5.3 and L87 6.2 V8s has been a common topic, but I'd like to take a poll and gather some real data from a sample group of owners. No need to comment with mileage or anything, just a Yes or No answer will suffice.
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