JDuncan

Update: no update. I'm told the senior advisor finally got the 'report' together and forwarded it to the district manager sometime between last Friday afternoon and this morning. Calling daily to remind him what a nice guy I am. @Jagerschnapps1 Yours also went down with a 4-5-6 failure? Was the fluid distressed when you changed it 40k mi ago?

Searched a few keywords but didn't find much. Hoping you guys can give me some insight and/or a sanity-check (or maybe just give me a shoulder to cry on; sorry for the novel). BLUF: 5.3 6L80 w/ 59k commuting to work last week, accelerating with traffic from a light, trans hits the 3-4 shift, but 4th might as well be neutral. Throws P0796. Forward & reverse work normal @ low speed, 4th gear is nowhere to be found. Fluid on dipstick bright red/orange, no burnt smell, no glitter. Googlefu TSB 16-NA-027. Powertrain warranty expired last September. Dealer says no foreplay, it'll be $5500 for a new trans. GMCA is up to 50% coverage on a dealer rebuild. I'm escalating. Saga ongoing. Full story: I bought my 2015 RCSB SLE 4x4 5.3 about 5yrs ago from a local Honda dealer, fresh off a trade. It had 5700mi on the clock and was an unmolested cream puff; clean history, GMC dealer serviced. 1st owner took delivery SEP15, I signed AUG16. At the time I had just bought a really rural house and needed something capable in weather that could haul supplies and materials. I don't tow at all, never been stuck, don't hotrod, and haven't hauled anywhere close to max capacity, so I think the truck lives a mostly easy life; I just need rugged and reliable for family use in inclement weather and exigent circumstance, and deliberately picked a young truck with lots of warranty left (and, I was financing, and I have feelings about financing cars out of warranty). Since then, I've racked up about 10k mi/yr, always lubricated at the local GMC dealer, never tuned or programed; powertrain 100% stock. I did succumb to a 2" level and 285/65-18 KO2s about 30k mi ago, and I'm not afraid of tackling normal wear items on the driveway (air filters, brakes, etc). I also keep an eye on fluids and usual old-school auto checkpoints. As long as I've owned it, the truck has never given me any problems at all. So, when I made my final payment last month I was feeling pretty good, looking forward to several years of low-cost ownership just keeping up with maintenance and wear items, maybe finally throwing on a tune, and enjoying a unique truck with tons of utility tweaked to my use case. Fast forward to last Monday morning, commuting in to the office, stoplight traffic. Accelerating from a light with the flow of commuter cars, transmission rowing up the gears, as she goes to hit 4th, forward acceleration ceases and the throttle disconnects from the tires. Revs out a few kRPM and I realize something is horribly askew, so I hit the flashers and dive into a shopping center parking lot to check it out. I check reverse, neutral, and drive; all normal. Pick up a little more speed and sure enough, 4th is nowhere to be found. Check tow/haul mode and manual shift/gear. Consistent: all normal until 4th. No noises. No shudder. No code, until at about this point, the CEL lights up. I dust off my cheapie scan tool I keep in the bed box and pull down a P0700 and P0796. I text a few GM-geek friends for a sanity-check and pull the tranny dipstick; balls-on level, clear red/orange, normal smell, no visible particulate/glitter. I consider limping it to the dealer about 10mi away. Then a TSB that seems to align with my symptoms a little too perfectly comes to my attention: https://www.tsbsearch.com/GMC/16-NA-027 So I figure if something IS broken in there, it would probably be a bad idea to limp anywhere. Out comes the tow truck, and off to the dealer we go. The next day the dealer calls and (more nicely than this) says "Pound sand, you're out of warranty. New trans is $5500. Not worth the T&M for a rebuild." Now, I'm more of a "catch 'em with honey" type, and I realize the service writer is just a mouthpiece for the computer screen, so with some controlled breathing we establish their technician is aware of the TSB, hasn't yet seen anything inconsistent with that bulletin, and that if this happened 9mos ago this would be a cut-n-dry warranty repair. I mention the whole situation leaves a metallic taste in my mouth to say the least; 13% out of warranty on time, but 40% inside warranty by mileage, and staring down the barrel of $5500 unplanned expense, less than 1mo since payoff. I ask for contact info of someone who has discretion in these matters. Dealer says they'll make a few calls. The following day, I get the "good news, GMC will pick up 50% of the repair, but only a dealer rebuild with parts replacement." Progress, at least. I ask the service writer what they would do if they were in my position in this situation. They say they'd file a case with GMCA. So that's what I did. By last Thursday, I was in contact with a "senior advisor" that would look into the case. I explained everything that I just typed out above. They said they would look into it and get back to me. By this time, I'm internetting the 6L80 and eventually come across this, https://youtu.be/d4OYRNIpJzI?t=754 which posits the 4-5-6 failure is a known issue due to a supplier quality problem (weld porosity) that was later corrected. I'm tending to believe my truck's build date in late '14 increases the chances this could be the issue. Today, I followed up with the GMCA advisor. I was told GM agreed to add $250 to the coverage amount. I was also told that a factor in that decision was my denial of a dealer-recommend transmission flush last fall. I pointed out that so far, no one has indicated to me that the condition of the fluid was in any way a known contributor to my failure. Advisor says he can go up to $500 unilaterally. "How about multilaterally?" So we're escalating. So, if you've made it this far, thanks for listening. Here are the sanity-checks and questions for the group, TIA: 1) Can the trans experts here think of anything else that could've nuked my trans like this? 2) Could skipping the '45k mi trans fluid service' last year have contributed to my trans failing? Was it wrong to just periodically eyeball the dipstick, thinking "I'm not stressing the truck, this fluid tastes fine"? 3) How comfortable should I be with a dealer parts-swap rebuild vs. crate (vs. reputable local shop) transmission? 4) Anyone local to the DMV have a shop they'd recommended in particular? 5) Am I wrong for pursuing the warranty coverage? Should I expect to pound sand here? 6) If not, are there any other angles I should pursue with GM? I'm in the NoVa/DC metro area, FWIW. Does the dealer sound like they're doing everything they should? For sticking around, here's a few glamour shots, including the lighting & bumper mods I did last month with a whole round of wear maintenance as a gift to myself for finally managing to pay off a note on something that's not garbage. What a dickpunch. Touche universe.

I'm a HUGE fan of the RCSB; love the maneuverability of the short wheelbase. You guys have some amazing trucks; inspirational to say the least. Here's mine: 2" level, 285/65r18 KO2s, Softopper and a few misc. bits. (shamefully dirty; pic was just after tires got installed)

Thanks for the reply, Sean. The battery never occurred to me as the truck's never been slow to crank and all indicators are nominal, but it does fit with the symptoms in that I've never seen it choke after the alternator has run for a while. And, as I think about it, the battery is the OE unit, now 4 years old, so it's probably due for a replacement anyway. I'll give that a try.

Another 2015 Sierra here; happens sporadically to me too. Like, REALLY sporadic. No more than 15 or 20 times in the last 2 years. This also seems to be a somewhat obscure issue, so I'm going to lay in a little extra detail here as a datapoint for community use if anyone else has this issue and manages to stumble across this thread. The suspect truck gets driven year round in the mid-atlantic; 2-5 days/wk - 40mi commutes, errands runabout, weekend stuff, etc - usually. Currently the odometer's sitting at 36k miles. Overall, it's been a great truck; none of the issues that surround this thread on the forum. Moderately accessorized, but otherwise stock. Speaking of the issue, you know your drive is going to get a dose of zen as soon as you hop in because there's no chime when keying the ignition, and like others here report, no synthetic noise whatsoever. All screens/gizmos seem to work normally. Settings still set. The first few times, early on, cycling the ignition would somewhat reliably bring it back right away; later, I'd need to crack the door to cycle RAP too. A year-ish ago it started only coming back after driving a few minutes and then cycling the ignition. Lately it's been a stubborn bitch, so I just have to wait/drive it out and relax for a 40min commute to the soothing sounds of a smartphone and wind. Also seems to be happening more often. Specifically, twice in the past week which is why I'm sending up my flare in here. I used to think it was thermally related as it seems to happen less in the summer, has never happened for more than an hour of so of driving [so far] and it's never happened after the truck had come up to temp in the prior hour or two (typical runabout usage, road trips, etc). But becoming more frequent and less responsive to digital crotch-kicks, instead make me think one of the computers is [slowly] failing. It's annoying AF, and ironically not the worst thing if it continues to get worse because eventually it'll choke in front of someone with enough expensive parts on hand they can tell me what failed, and it can be replaced. But, if it takes another 2 years to get to that point, my warranty is hosed and I'm out of pocket for whatever module of crap began its death on GM's dime. And on principle, that blows. The rub is the truck has [historically] gone for long, seemingly random, periods of time never acting up - weeks/months - so this shameless thread resurrection is to pose the question: Does anyone here have resolution on the posts above, or any ideas on how to get this problem in front of a service tech?

Re: a color matched grille, I'd recommend 2 things: 1) patience & 2) eBay $400+ was WAY too rich for my blood, so on a whim I set up one of those e-mailed product alerts on eBay, had the correct OE part number in my back pocket, and waited. A few weeks later, I picked up a AT factory color matched grille for my '15 SLE, for something like $240 shipped; just had to wait for the right supplier to clear out the right warehouse. (BTW, I have a clean chrome grille for sale) Ended up looking like this for now; like you, I'm trying to decide what to do with the bumpers. I originally tried Anthracite Gray Plastidip, front didn't last too long; still on the rear. Current front-runner option is Line-X, but I need to find a competent vinyl shop in my area to compare.

Great looking truck! Really like all the small details. Cant wait to see how the audio system turns out! Been thinking about this for a while.

This is a slick idea I wish I'd thought of. I tapped the high beam in my Sierra off the shutter trigger on the headlight harness, then ran to a lit "arming" switch in the overhead console. Position 1 - on w/ high beams (switch light on when light bar on) Position 2 - off BTW, with a few diodes wired up at the switch, you could get multi-mode function w/ one relay.

Man, there are some truly inspirational RCSBs on this thread. Very impressive, gentlemen! Here's my RCSB - just a 2" level and some cosmetic mods... for now:

This is SICK! Can you share any info on the turbo setup? Size, what's involved, kit, did a shop do the work for you?

Thank you Thank you!!! That's what I was hoping to hear! Since my local GMC dealer clearly isn't the right place to help me, would any normal tire shop be able to activate the OEM GM sensors in my wheels? BTW, here they are on my truck; dark grey dip coming soon:

Stopped by the GMC dealer this afternoon to have them relearn/program TPMS sensors on my '15 Sierra RCSB. Bottom line: they said it is impossible to do so. Here's the back story: I swapped my OEM 17" wheel/tire combo for OEM 18" wheels/tires taken off another 14-15 Sierra. I bought them locally off CL. Figuring the new set has OEM TPMS sensors from the same generation truck, and having read no overt warnings here or elsewhere, I thought it would be a no-brainer to have the local dealer relearn/reprogram the TPMS for the new OEM wheel/tire combo. I listed my original wheels on CL, and due to travel scheduling, lined up a deal and sold them before I had a chance to go see the dealer. After an hour in the waiting room this afternoon, here's what the delaer told me: 1) TPMS sensors come with a "Registration Code" printed on the OE packaging. That code is required to program the truck to read the sensors, and it is impossible to use any sensor not already programmed to the truck without that code. 2) TPMS sensors are model-year specific; a sensor from a '14 wont work on a '15, etc. 3) IF I still had my original wheels, the dealer would dismount everything, swap the sensors, and remount/balance; at a cost of ~$250 4) The only option remaining at the dealer service counter would be NEW TPMS sensors and install; at a cost of ~$500 How much of the above is fact vs. fiction? Have any of you guys been in this situation before? What would you recommend? I've been going to this dealer for a few years now; they've always seemed knowledgeable and have never done wrong by me, but this "registration code" stuff caught me by surprise. Any info or insight you guys can provide would be appreciated. Right now, it sounds like I'm just going to have to live with the idiot light on the dash until the budget allows for the K02s I've had my eye on; now that much further away with the addition of TPMS sensors.