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Heat is the enemy of many things, from automotive fluids too electronics.

After I wrote that reply I went for a ride. 85 F out. So trans started at 85 F and it shifted the same as it did an hour latter at 168 F. I've never actually recorded the to cold to shift point but it is under 32 F before they start hanging on to a lower gear or leaving the converter unlocked. Both intended to heat fluid. Yes, brake or bake. Absolutely. Your welcome. True research ended decades ago. Field trials are still in play. There is a thing called oxidation onset temperature. This is the heat related oxidation not the O2 exposure kind. For mineral oil that starts at 140 F. So what happens after 140 F? Each 20 F cuts fluid life in half! Does using a Full Synthetic improve that? Yes! By how much? Depends on the base oil type and a few other factors. But enough to notice. Some esters are even higher. There are even synergies between types the will raise it higher than any one component is alone. Then there is "Hindered" oils. Antioxidant additives. Hindered Polyol Esters can sit at 500 F for years in a turbine. When a blender brags his oil will 'take 500 F" in service he doesn't specify for how long. Water will dance on a 500 F hot plate for several seconds. @newdude put up a chart showing the relationship between fluid temperature and it's life in an automatic transmission. Here's a version of that chart for Group III based oils. These temperatures are those in the pan as observed as 'normal'. that is you drive as you do for as long as you do under what load you ask of it and whatever that temperature is this graph applies to. Flash temperatures of a few minutes isn't what his means. Note that fluids held at a constant 240 F have a service life of only 20K miles. 220 F explains the factory exchange limit, eh? My equipment I keep under 180 F and I'm good if the cooler will hold it as low as 140 F. But that's me.

It is working as designed. NHT and non NHT trucks have the same exact transmission cooling setup. NHT just gets a larger radiator. The transmission cooler loop on these is as follows. -Transmission out goes into an oil to water heat exchanger (item #1 in the first illustration below). This exchanger has engine coolant opposite the transmission fluid and uses engine coolant to warm and then regulate the transmission fluid temperature when its in the operating window. - From the cooler it goes to a thermal bypass valve (item #11 in the 2nd illustration below). If the ATF has not reached the temp to open the bypass (194F), it loops back. - When it reaches 194F, the thermostat opens and ATF then flows out to the oil to air auxiliary cooler (item #17 in the 2nd illustration) at the front of the truck. From there it goes back to the transmission. Your only fix would be to swap for the PPE thermal bypass delete block which will open the loop to the aux cooler all the time. It will STILL run warm, probably 170-200F, but that's as low as you'll get it as its still flowing through the oil to water exchanger.

Given your chart GB, and the anecdotes we've seen here of what I think were 10L80 transmissions running consistently at 200 degrees and higher under light-ish towing loads I'm very pleased that mine stays around 145, even in high ambient temps. Of course the proof will be in the pudding when I actually pull one of my trailers, but at this point it appears that I won't see temps in the "dangerous" ranges for my tranny.

It sure does. You have to look a little closer. This is mine.

O2's not working well will alter the AFR and make em stink. Drop that cat in a bucket of hot soapy water then pressure wash the internals, what you can reach. Brings a good many of them back to life if it's soot and not poisoned.

Look at the numbers on the stickers in the door jam...

And Google AI says......... Yes, your truck can technically handle it, but you will be right at or near its maximum limit. A 2016 Chevrolet Silverado 1500 High Country with a 6.5-foot bed has a maximum payload capacity of approximately 1,770 pounds.Weight RealitiesLoad weight: Half a cord of dry hardwood weighs roughly 1,100 to 1,500 pounds depending on the wood type (like oak or hickory).Payload limit: Payload includes the weight of the wood, you, any passengers, and a full tank of gas.The math: If you weigh 200 pounds and have a full tank of gas, a 1,500-pound load of wood puts you right at that 1,770-pound ceiling.Safety TipsCheck the yellow and white sticker on your driver-side door jamb for your truck's exact payload number, as high-end luxury trims with extra features have slightly lower capacities than basic trucks.Expect the rear end to sag noticeably.Drive carefully, avoid sudden turns or stops, and keep speeds low if you have to travel a distance.

Clearances haven’t changed in decades and looking at the oil spec of our same engines in other countries pretty much gives that argument up anyway. But yes, people still try. Regardless, GM and all other automakers always knew the real risk is not with viscosity too high, but too low. They still played the game and finally have to admit defeat on this round. Unfortunately they gave the DEXOS license to the M1 AFE 0w30, and not the much stouter ESP version which has a 3.5 HTHS. But hey, if a guy wanted to ignore DEXOS but still stay relatively “warranty safe” the ESP 0w30 is still API and seems to be a decent option. Certainly puts owners in a better spot than in the previous gen trucks where nothing API 0w20 would ever actually work.

How many years have I pointed out every point in that link to the folks here and been avalanched with criticisms and outright hostilities at times? I ran counter to even the great CUSTOMBOSS and Lake Speed Jr and the half dozen experts on YouTube and in the final.....GM, Physics (Stribeck) backs that Grumpy old Bear. Honestly, I never said a thing engineering hadn't studied silly and laid in concrete during WWII. But I'm old, the information is old and yet, the Laws of Physics are eternal. Okay there is one exception. I vehemently disagree with their use of the word 'tolerances' when what it meant is "clearance". The clearance is the distance between two objects. The tolerance is the degree of acceptable variation permitted in that clearance. I.E., piston to bore clearance is 0.004" with a tolerance of +/- .0002" so the clearance is in specification if it lies between 0.0038" and 0.0042". Cutting that 'tolerance in half has ZERO impact on lubrication requirements. Makes for more difficulty in manufacturing. But a tighter clearance 'MAY'. Depends on finish. Anyway.... It's one of those statements made by people to make themselves look smarter than they are to convince people who are as un-enlighten as they seem to manipulate their behaviors. But hey, the blind leading the blind puts them both in the pit.

The 10L90 was used in high horsepower cars and SUVs (higher HP/torque version of 10L80). The HD trucks have the 10L1000 which was co-developed with Allison and is not related to the 10L80/90 which was co-developed with Ford. The 10L1000 replaced the 6L90 used with gas HD trucks in the current generation of the HD trucks.

I know the upfitter switch deal well; my truck didn't have it, so in one day I retrofitted/wired the kit, and since I knew I'd have several panels off, I did the same day a High Country cluster, and console charging/cooling. That charger cooling tube was the worst part of the deal. The gauges are MaxTow. I don't need an iDash, as the HC cluster has all that information, and I'm using the OBD for a pass-through for the Intellihaul cameras? or the GM dash camera?, anyway. I'm ending up going under the hood to the fuse box. I identified constant hot/switched hot/illumination and have some piggyback taps in. Just waiting for an 4-wire 18-gauge cable to come in the 29th to finish. I already ran the sensors, and have the gauges/pod mounted. If I could've found what I needed on the fuse panel by the light switch, they'd be up and going.

Next Friday will be my 6 week point from my right knee replacement. The surgeon says it will be fine if I choose to drive after this checkup. I know I could drive now but best to do as my surgeon (and my wife) tell me. Richard compared being 62 to 72. I remember when I was in my early 60's I was experiencing slow but regular decline in my mobility. Thanks to good medical support, i continued to fight the speed and spread of this decline. During my 60's I worked on non-surgical methods and just when I turned 70, my orthopedic surgeon recommended joint replacements. In a little over a year, I had one shoulder and both knees replaced. This hasn't been a terribly fun experience, but worth the discomfort as my future mobility health trajectory has reversed. It is a treat to now be watching my mobility. balance and confidence steadily improve!

google "bathub failure curve". Basically, any part of the vehicle can fail at any time. It starts off as being more likely (early failure), then the failure rate goes down (but does not go to zero), then it goes up over time because it wears/ages out.

2024 2500 gasser with 47,000 miles. Driving on interstate Friday when my truck shudders, downshifts, and I get the above message with check engine light. Transmission would not upshift. I had to drive home 2 hours at 65 mph at 3600 RPM with transmission temps 190-200 degrees. Got it to the dealer Monday. They ran the code and said the #1 valve body was malfunctioning in the transmission. Miraculously, they had the part in stock and I had a new valve body installed that day with new transmission fluid/filter. Thankfully, all under warranty. Shout out to Everett Chevrolet in Hickory, NC.

We understand that intermittent AC concerns are inconvenient, @tjonesdfw, especially since they often do not show themselves when we want or need them to. We would like the opportunity to learn more about your experience with your Sierra and explore the best path of assistance moving forward. To begin, please visit: https://s.gmc.com/support-request and fill out the support request form with all pertinent details. This form helps our team gather the right information and ensures your request is routed appropriately.

I had a strange problem with my Avalanche. Yearly once the temperature started getting hot. It would freeze me out going to my walking trail about 8 miles. Nothing but hot air going home. My machanic would put the Freon in the machine vacuum the system. No leaks put the Freon back, good for the year. My brothers truck wouldn’t work at all until he did the same procedure. I believe he finally changed the expansion valve to solve his problem.

Shouldn't the fault be saved and able to be pulled with a reader? Otherwise, maybe start taking pictures of it which will have a date and time stamp, so you can build your case.

Rear wheels lock up when it tries to downshift while towing (going uphill with our 5th-wheel RV). This is the known problem that 463,000 trucks were recalled and programed to try and let the owner know about 10,000 miles before a lock-up happens (feels like you ran over a telephone pole). Ours just happens to be one of the "lucky" ones that locks up without prior warning. We took it into nearest Chevy dealer (out in CA). After 2 weeks waiting, we were told by the dealer they didn't need to do anything relating to the recall because it wasn't throwing the PO747 error code. I offered to take a technician up a hill on the highway with our 13,000 lbs 5th-wheel in tow, but they declined. They asked us to wait in California (2100 miles from our home) for another 8 weeks for a GM engineer to come to the dealership and look at it. We declined and put our camper in storage and drove the truck home to be serviced local. We can't wait the 8-10 weeks for a GM engineer. Does anyone know who to contact at GM to get our costs covered? (note: We have filed reports with NHTSA and opened a file with the GM Customer Care line- Who told us we were covered by the recall, but because they were not part of the GM technical service (TAC), they had no authorization to tell the dealer what to do as dealers are independently owned.) Are we forced into a lawsuit to recover our repair costs and expenses for what should be a warranty repair? And imagine our surprise when we learned that despite the branding on the hood, we didn't have an Allison transmission. Reference: Special Coverage N242454441-03

Hi RB, I sympathize with your dilemma ~ we have a 23 3500HD with a 6.6 / 'Allison'. I have been a mechanic for 51 years (retired now) and have been a GM guy for many years. I'm just waiting for the dreaded incident to happen while towing our 10K trailer. We have 20,000 on our rig and this situation is inexcusable. Flashing your TCU to warn you ahead of time is bogus. Ford pulled that crap on their Triton V-8s while I was a fleet district mechanic. After that didn't work (recall) they forced us to replace spark plugs and charged per hour for those that broke off in the head. All on trucks that 'should have been ' under emission warranty but weren't because they were over 8600 GVW. Still a F-250! I have been weighing purchasing the upgraded valve body from Next Gen Drivetrain and installing it, just to avoid grenading the rest of the transmission and drive train ~ not to mention the possibility of a major wreck. The other option is to buy their valve body upgrade kit and install yourself if capable. Down the line, I would hope there would be a refund for the purchase / repair costs. The understanding is that GM purportedly does not have the parts to repair the defective units. This whole thing is a major malfunction. Oh ~ for shares the same transmission (it was a joint venture with GM ~ they just paid to use the name 'Allison') Fords don't seem to suffer the issue as they don't have the crappy valve body in them. I wish you the very best in your journey. I think we all have a fight ahead of us to get this rectified. Greg

And then 5 years from now, a law firm pockets 66% of the funds and each owner gets a check for $28

Yes, multiple people have considered starting a class action lawsuit.

Has anyone considered starting a class action lawsuit?

Your on the track, after you have the spoiler off, clean the channel with the window and cab really good, and just fill it up with flowable silicone, I used 2 full tubes from an auto parts store, it will never leak again.

After seeing a number of posts in online groups with similar electrical problems as mine, I did a poll of each group. 210 responded and 23 percent of them who had a 2024 reported electrical issues. I recognize this isn't a scientific poll, but this is significant for a truck that has been in circulation for such a short time. The problems vary greatly. My safety features work only intermittently. Blindspot detection, parking sensors, and lane departure all come and go. My parking brake also disconnects/reconnects, even after having the module replaced. It even locked up my trailer brakes once at a stop, and this was after the module was replaced. Others have had their trucks need to be towed, windows go up and down, and high beams only work for 5 seconds at a time. Those are just off the top of my head.

I posted this in other sub forums since it concerns all HD owners. Now debating if I should just go ahead and do the Nextgen upgrade, or just ride it till warranty is gone, and ditch the entire truck. Flipside, is what would you trade into that doesn't have issues? Fair point about picking a truck you like, address whatever flaw it has, and go on with life.

Over 22,000 miles on mine now, a 2024 6.6 gasser silverado, still puuurrrrs, no ping, no knock, just smooth sounding. It just towed 1,600 miles south, a simple 9,500lbs 5ver and smooth. All on 87 octane, some normal non ethanol but mostly stuck with ethanol blended fuel. I like the windows down as much as i can, so i get a good feel for how it sounds. It sounds and runs the same with the 2 tanks of 91 i ran through it for the heck of it a wile ago, as 87. My friends 2024 3500 6.6 gasser GMC also no ping or strange noise, just smooth sounding. The 6.2 and 6.6 are not the same motor.

Read post #2 above, tells you everything you need to know about what to use

LockNLube is the best gun. No more using the lever against something while you hold the zerk on. https://locknlube.com/ NLGI #2 grade. Any will work.

We've done a bunch of them. Very common failure. They don't sell the park position switch separate from the shift control assembly which is stupid, because they ended up selling a switch on some other products like 2016-2019 Malibu, 2018-2019 Traverse, 2019 Blazer, and another car or two as those were having the same issue for years (but these have a console mounted shifter not column mounted).

This is my 2nd Trail Boss with a leaking slider, both of them I bought new. The first one I fixed myself by replacing the slider with a solid window (details are somewhere in the massive leak thread). The second one I wanted to keep the slider and permanently seal before it ever leaked. I've had the truck over a year and finally got around to it. Since I was dropping the headliner I also added the camera rearview mirror and hard-wired my radar detector. I dropped the headliner and removed the spoiler. I cleaned the top of the window channel with all purpose cleaner and a detail brush and dried it. I taped the top of the glass and back of the cab with some little tape ball dams at the ends. I warmed the area up with a heat gun so it would flow then I applied self-leveling sealer SEM 39387 then I hit it with the gun a little more to draw out air bubbles. After that cured, I put 3m strip caulk on all of the spoiler bolts and nuts and re-installed the spoiler. The self-leveling sealer had the exact effect I wanted, it bridged from the glass to the body and covered up the plastic slider frame that cracks and leaks. There were no cracks in the frame this time. I also noticed they are putting a little sealer on the nuts that hold the spoiler on, but it's not adequate. The way I did this it should never leak from the glass or the spoiler holes. The mirror upgrade was easy, swap the brake light, add the cable and swap the mirror. Plug-and-play.