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Coming home from a four-hour trip Sunday towing a small utility trailer, my truck dropped to idle while at speed on the interstate just a few miles from home. I was lucky and able to pull over to an exit ramp with zero power. While coasting the display popped up saying reduced power for a couple of seconds and the engine light came on. While still on the exit, all power restored, message went away, and I was able to make it home on back roads. While it was still running I pulled three codes: P0087, P129F and P228B. Cut it off, unloaded everything and then went to move the trailer. It turned over for a few seconds then busted off (longer than normal). As soon as I put it in gear it shut off. Got it to the dealership and awaiting the results. Truck only has 1,404 miles on it and was delivered from Flint a few weeks ago. All displays read fine, fuel filter, DEF fluid, etc. Engine light still on. Just FYI to add to the list of L5P problems

Well, seeing as how I can't find much on this subject no matter what forum I go to, why not try to start the discussion here and see what kind of following I can get and see where we end up. If you're reading this thread, chances are you have thought about modifying or swapping out your current transmission in your 2014+ GM truck. In my case, I don't mind my 6L80 in my truck. It does fine for what I do right now and it's holding up just fine, but I think the big issue is when you start to search for big power (like I'm starting to do), that 6L80 is not going to hold very much (or so we think). Now, let's all face it. We've seen posts after posts, comments after comments, photos, videos, etc. of guys with built motors with turbos or prochargers shooting down the quarter mile in search for the best time on these 6L80s. Some say they're completely stock, others have them built, and we all ask ourselves the same question: Reliability. How well are these transmissions going to hold up to the abuse on the track? Especially if you want to make it a fast street/strip truck and drive it back home to the garage afterwords. We know for a fact that 6L90s can hold quite a bit of power. Even though I've mostly seen it in Camaro ZL1 applications, there is a guy on YouTube (GuitarmaggedonZL1) who is running a stock 6L90 on stock converter making 1000HP (give or take on an unloaded dyno) and the transmission hasn't puked all over the ground just yet. (Exaggeration, I know.) So, needless to say, a 6L90 swap sounds nice, at first... After you figure the extra length and weight (and in my case, relocation of the transfer case and getting custom driveshafts made), it starts to look a bit unpromising, but still not out of the ball park yet since it will be able to handle the power some are seeking, but where these newer transmissions lack significantly if you want to do boosted applications at the track (or even just launch control on N/A), no one has developed a transbrake. Very, very few forums are talking about this, and only one video exists of a guy in his BMW testing out a transbrake on a 6L80/6L90, and who knows how reliable it is. So, now, you start to think: Well, gee. What can I do now? How about a TH400 or 4L80e swap? So far, I've seen few posts on that as well. No one is talking about it, and I think the biggest problem people seem to be facing is the new PCM: E92. Also possibly the fact that the TCM on the newer transmissions is inside the transmission and whatnot, but whether that plays a part in this, I don't know yet. Now, adapting a TH400 or 4L80e can be done (most likely with a different bellhousing since the bolt holes are in a slightly different spot), but you run into the issue of getting it to speak/cooperate/communicate with the new E92, which I don't think anyone has tried. The only video I've seen of anything working in this application was on a 1320Videos video with a Nova where they were using an LT4 long block (built motor to 388 C.I.) and twin turbos, and it had a powerglide in it. Don't know if it was a manual valve body or computer-controlled, but what I do know is that they used the factory computer to run the DI injection system and piggybacked the rest to an MS3 Pro. After dealing with some issues, they were able to make that thing boogy to a 9 second pass at 148mph. So, these engines have potential to haul ass, but we just haven't figured out how to crack the system. So, at this point, I'll just leave what I've discussed here and see where the thread goes from here, and I'm hoping people chime in and vendors are watching/listening. Even though the demand isn't hot for it right now, there's going to be a surge for good transmissions when people can buy these trucks/cars/motors/transmissions for pennies on the dollar. Unfortunately, I feel like we'll have to wait that long in order to see results, but oh well. Just to give you guys an example: In the next year or two (2019 or 2020), I'd like to go turbo with my truck. (Doing all the supporting mods before going there minus built bottom end until I see where I can get with stock bottom end before sending a rod through the block or oil pan) Ideally, it'd be best to have a transbrake in that application with 2-step, but can't do it on the new transmissions. So, 4L80 seems to be the option, but I can't do that either because no one supports adapters or harnesses to make them work with the new motors/ECUs. That's the boat I'm in. I like to research everything before I go whole hog into something. Risk assessment, I guess.

Hey guys so I did a 2019 Frontend Conversion to my 2015 Denali, with the Ram-Air style hood..... But trying to find a wire harness that converts from 2015 to the new lights, well that's easier said then done. So I was given this site by a friend that did this conversion to his truck.... I highly recommend this site, as they use GM plugs & the wires are all as good or better than stock..... Nothing wrong with that in my book. Check them out, they have E-mail if u have any questions & in my experience they get back to u in like an hour or less...... These harness are truly "Plug & Play". No cutting any wires, no guess work, all that is done for u.... They have the schematics for all the years & work off of them to make sure everything is correct.... Plus they check everyone before shipment..... Pic of my Denali, before & after. Their website also include. https://www.gen5diy.com/collections/14-18-sierra-p-p-harnesses

Seen alot of posts like this but none that quite answer my question. I have a 2018 Sierra 1500 Denali with the 6.2. I am thinking about installing an electric exhaust cut out before the muffler. (For arguments sake let's say my best friend is the warranty manager at my local dealership so I am not concerned about warranty mumbo) What I'd like to know is if I am going to run into any check engine light or any other messages popping up that she will pissed at me about it. I noticed alot of people with '14s and '15s not having issues with them but I feel like this 2018 has so many sensors and is so touchy that I'm hoping to hear from someone on here with the same year that has done it or knows of someone who has? I dont have any oxygen sensors back that far but is this engine computer smart enough to realize there is no backpressure from the muffler or something like that. I may just be being paranoid but really dont want to have to look at an idiot light over it. Wouldn't be worth it..or would it Any logical input would be very appreciated!

I recently bought a new 2018 Silverado 1500 Crew Cab LTZ with the 6.2 liter & 8 speed transmission. I bought the truck in Idaho (great deal) and drove it home to California. Since then I've only put a few hundred more miles on it, 1181 total miles to be precise. Yesterday the tranny started shifting really hard & clunking on downshifts. Today, when I put the truck into drive it barely moves! Obviously, the transmission is slipping as the engine revs but the truck doesn't really move much! Any info on if the truck can still be returned at this point or am I stuck rebuilding a brand new tranny? Doesn't seem right to have to go through this so soon! I hope GM will either let me return the truck completely or give me a brand new transmission. Any insight on what may happen would be appreciated! Thanks in advance!

I have a set of chevy LTZ wheels were on the truck about 2 or 3 days before being replaced. No TPMS. I'd say wheels have 20 miles on them. Perfect condition. 6 by 5.5 18 x 8.5 Located in west Arizona

I've read enough about these valves to want to clamp it in the full open position until I can delete it entirely when I get a cat-back exhaust. But, how in the hell do you clamp off the round ones on the 2018 trucks? Here's what mine looks like, and a simple hose clamp managed to slip off after only two days.

I've a 2018 GMC Acadia. It is a FWD 3.6L/6T70. Recently, I've not been able to move the shift lever to Low ranges. It was intermittent at first & today I was not able to shift it into low range at all. Wondering: if anyone else has experienced this?, Fix?, Bulletin? This is a potential safety issue. Thanx Bob

Hoping someone can help me find the part number to the rear driver side manual door locking pin/knob for a 2018 Silverado 1500? My buddy and I took apart my door to install subs in my truck and while he was trying to put the door panel back on he broke the lock pin/knob. i been trying to find one online with no luck. Now I’m hoping that if I at least get the part number or a diagram of inside the door somthing will pop up on the internet? i will attach some pictures below of what I need. Thanks!

I have a 2018 Chevy Silverado 1500 LT Z71 with 8000 miles. No modifications. Great truck, almost no issues but... I have owned this truck for 7 months now, and for the second time in the last couple months, it has left me stranded for around an hour each time. When i start the truck i receive the "Power steering reduced, drive with care" message. But unlike others i have read about, i can not turn the steering wheel with all of my strength. Also the truck will drive forward in this state, but not reverse, nor will the back up camera come on. And the AC and blower wont turn on unless i spin the dial a few times. Each time i have opened the hood and pulled out and plugged back in all the (really hot!) fuses and after about an hour the issue goes away and i can drive again. Why would the fuses be so hot just sitting in the parking lot, maybe they always are. who knows. I took it to the dealership and they are trying to recreate this issue, but since its only happened twice in 7 months that's not likely. So they told me next time this happens to have it towed. How inconvenient is that though! Cant they run diagnostics or troubleshoot with the many symptoms the truck has in this error state? I was hoping someone here has an idea i can tell this dealership to try since they don't have ideas of their own. Thanks!

Good morning everyone, I recently purchased a 2018 GMC Sierra Crew Cab SLT All-Terrain package. I'm personally wanting to install a leveling kit and I believe I've selected one. I've read a lot about leveling kits for 2017-18 trucks and this seems like a great kit. However, there isn't many reviews on this product by ReadyLift. The appeal of this lift is the UCA replacements and the <2" height it allows. I'm wanting to go with 305/55/20 or 285/60/20 tires with my stock AT wheels and I want as much clearance possible. I found maybe 2-3 members on here with this lift and I'll quote them below. My question is, will this work with my All-Terrain package? In the description of the kit it states, "Will not work on Z71 packaged vehicles with factory Rancho® struts." Yet on ReadyLift's website, there is nothing supporting that statement. Does anyone have any information or review for this kit? Thanks!

I'm trying to figure out what the max tire size is I can put on stock 20s in the 33" range. I'm looking at KO2s right now which I know BFGs run a little small. What is the max I can run if I level with a 2.0" level or if I run stock suspension? I have a 2018 Sierra Crew Cab NHT with stock 20" wheels. I tried doing some searching and I think I can fit a 33 no problem but then I see other posts that just confuse me on the matter.

Hello, I’m new to this forum so I’m not sure if this question has ever been posted? I have been looking all over the internet but just can’t seem to find an answer? I have a 2018 Silverado 1500 Custom And I was wondering if it’s possible to swap my grille to a Z71 grille? I’m not sure if the Z71 grille is a different shape then my front end? I’m not a big fan of the black honeycomb look being that I’m going for a more sleek all white look. (Need to paint doors and mirror caps) If I can’t swap grills does anyone know where I can buy the grille insterts from a z71 grille? first 2 pictures are of my truck and second is a picture of the Z71 grille I want.

Have a custom mid-pipe I built to install an aftermarket muffler (Magnaflow 12909) in my 2015 2500hd 6.0 truck. I removed the muffler and went back to stock so have this left over. This makes a cleaner install and saves your mid pipe if you want to revert back to stock. The aftermarket mufflers don't have as much offset as factory and the factory mid-pipe has a offset in it that accounts for that. With this straight mid-pipe it works perfect with the less offset of the aftermarket muffler and allows everything to be installed level with the truck. Here is my post about the muffler with additional info: I had this on a crew cab, 6.5' bed 4x4 truck. I'm sure other cab/bed configurations might need this lengthened or shortened but at least the hard part of the flange and hangers are done. Asking $75 for this custom mid-pipe. How it looked installed. muffler not included. Factory muffler to show the drop offset in the original mid-pipe.

John Goreham Contributing Writer, GM-Trucks.com 10-26-2017 GM-Trucks.com was invited to a quick-drive event including the all-new GMC Terrain SLT this past week. The new Terrain and the Chevy version, the Equinox, are two of GM’s most important vehicles. There is no larger automotive segment in the U.S. market than compact crossovers. Yes, individual truck models (The F-150 and Silverado) outsell the top compact crossover, but more crossovers are sold each month. GM was a little late to see the emerging formula, and the outgoing Equinox and Terrain grew long in the tooth. Nissan’s Rogue, Toyota’s RAV4, and Honda’s CR-V began to outsell the GM twins by huge margins. In response, GM has now closely adopted the size, and specifications of the top sellers. Sales are responding, and the Equinox was coming danger close to third place ahead of the CR-V – until the Equinox plant in Canada went on strike for a month. Our short drive took us over all forms of roads including a short stretch of highway. The drive answered a lot of questions for us, but the Monroney (window sticker) raised new ones. Here’s our take. 2018 GM Terrain AWD SLT – The Drive The new Terrain drives well. The new 2.0-liter turbocharged engine is responsive and plenty powerful to compete with the best engine in the class, Honda’s 1.5-liter turbo introduced 15 months ago. The 2.0-liter is one of two options GMC will sell alongside the volume engine the new 1.5-liter turbo. The other is the new 1.6-liter diesel engine. The optional 2.0-liter turbo adds $1,895 to the cost of the Terrain. In combination with the 9-speed auto, the Terrain felt good in all situations. Handling was tight and steering sharp. The Terrain is also relatively comfortable over bumps. 2018 GM Terrain AWD SLT – Interior and Comfort The interior quality is better than most of the Terrain’s competitors in our opinion. Materials and craftsmanship are above the mainstream class, and below the luxury class. The seat was high-up in the Terrain. By that we mean we felt it was higher up than other crossovers its type. This is a just a “seat of the pants” observation. 2018 GM Terrain AWD SLT – Pricing and Value The hard part for us was the difference in price between the Terrain SLT with the options our tester had and the CR-V AWD Touring, the top-spec Honda. The CR-V is a $35K vehicle with everything. The SLT Terrain we drove was priced at $42,045. $7K is a big delta in this segment and a 20% gap is hard to justify. However, GMC does have other trims that will be priced lower and so too does Chevy. The next item we noticed of concern was fuel costs. The Terrain AWD’s combined fuel economy is 23 MPG with the 2.0-liter engine, and 26 MPG with the 1.5-liter engine. Honda’s CR-V is 29 MPG. The Terrain we drove was rated with Premium, which we feel is crazy for any mainstream vehicle. We did a little more research and found that the diesel Terrain has the same annual fuel costs as the gasoline CR-V. We know from having asked GM that the deisel Terrain's 0-60 MPH time is about 10 seconds. Pretty slow for a modern compact crossover. GMC may well have found a sweet spot just above the level of the mainstream sales leaders in the compact crossover segment. We hope that is the case. 2018 GM Terrain AWD SLT – Safety Safety is a key consideration for compact crossover buyers. Our Terrain tester had added in $1,335 for active safety systems like forward collision prevention and lane keeping assist. The top sellers, RAV4 and Nissan Rogue, now include these systems on all trims at no added cost. Honda’s CR-V includes it on all trims but the base model. We suspect the new Terrain will score high on the IIHS testing. 2018 GM Terrain AWD SLT – Conclusions Without a full week of testing, we can’t say whether the new GMC Terrain AWD SLT is now the best mainstream compact crossover. Based on our short time with the new Terrain, we can say for sure that the look of the Terrain SLT AWD 2.0T is attractive and the perceived quality is competitive with the best. The drive may well be better than the CR-V, due in part to the optional engine. We hope we have the opportunity to do a full test and review soon. The Terrain is an exciting new vehicle in the largest segment and deserves a close look.

Hey all, I own a 2018 Silverado 2500HD LTZ Z71...The damn headlights are that terrible yellow color, Did Chevy not put LED lights on any of the 2500 models? Has anyone replaced the whole light assembly or even just bulbs to achieve the clearer look? If so please share and checkout the photo below of my headlights compared to the illuminated bow tie. Thanks for the help.

Just got a new 2018 Sierra with more bells and whistles than I've ever seen in a truck before. Sure learning a lot on these forums. The catch can thing has my interest, I never even knew that was a problem, never had a direct injection vehicle before. I'm looking under the hood on this thing and although it is difficult to see much it looks like there are two PCV valves, assuming that's what I think I'm seeing. They are right up front of the engine, one each side, with short tubes going into the intake air plenum. See attached photo of the front left side of the engine. So question #1, are two PCVs what I am seeing? Question #2, if so then I need either two catch cans, or one that does double duty, right? I'm a little confident that the answers to my questions will be yes (still appreciate confirmation though) and if so this will be a plumbing nightmare. This truck has the eAssist which means the only open space for a can is the front left corner where the battery used to be, on eAssist it's up in the back right corner of the engine bay. And, there is no room at all left in that part of the engine bay, it is packed. So I guess question #3 is, anyone come up with a creative way of solving this problem, besides hoses all across the top of the engine? Thanks in advance for responses.

I’m sure this had been asked 20x but I can’t seem to find it. I’m looking to add some tow mirrors to my 2018 Sierra elevation package. Has power mirrors, non power fold, has defrost, and does not have turn signal. Which are best mirrors for this? Also can I hook into wiring harness and add turn signal as well? Thanks again!

Hey, so I am trying to replace the speaker wire in my rear door speakers and I cannot get the panel off that is on the column between the front door and rear door. This column panel has the speaker wires running up it into my rear door. How do I remove the panel without breaking the little red Clips inside? Thanks, Hunter

Bought a 2017 Chervrolet Silverado crew cab 4wd Lt from Gateway Chevrolet in Avondale, Arizona. It only had 2800 miles when I bought it, certified preowned. This was back in November 2017, few months ago I realized the truck had about a dozen dime sized dents throughout the roof, very slight dents but definitely there. It infuriates me how they didn't disclose this to me, I bought the truck for an unreasonably expensive price considering it had dents on the roof. It angers me because The truck cost me 38,000 dollars and they didn't disclose dents on the roof, body damage!!! it will cost me nearly a thousand dollars to repair. I called Chevrolet and of course there is nothing they will do about it. I called the dealership and I haven't even been able to get through to a person in charge, they keep on giving me the run around. I am so pissed, I can't believe Chevrolet did this to me, I feel lied to I decided to buy Chevrolet because of the reputation it has but am now wishing I would have bought a ford instead.

So I've had my truck now for 2-3 months and it is now sitting at 3295 miles and every now and then it shifts hard or sloppy but i can make it shift hard by flooring it which obviously happens when doing this but the weird part is not flooring it is when i let off the gas and when i come to a stop the downshifts are harsh. Now i know i could be breaking it in but even my father who used it for a week said it should be checked out and he is quite the Chevy enthusiast himself. Is there any known problems with the 6 speed in my truck? its a 2018 double cab lt z71 4x4 with the 5.3l. -edit: it also shifts hard when using manual mode or low whatever you like to call it just putting it out there.

Ok so this is my first post on hear but im not new to this place ive used this forum thousands of times in the past as I am only 18years old i started off in a 03 gmc 1500 short bed reg cab stick shift, but up here in mass 2wd wasnt gonna cut it so after that I had a trailblazer for the past year and now Ive been lucky enough to get back into trucks with my new 1500 that i'm leasing, its an LT Z71 with 4wd and the 5.3. Im perfectly happy with how the trukc is as of now but I definitely want/"need' it to be leveled as my whole family Cousins, aunts, uncles, father, and mother have atleast a leveling kit or just a beefy vehicle as now im the only one without some ground clearance, but i dont know which leveling kit is the best choice as i want to stay under 3 inches. So if anyone could help me it would be great id like to know the best kits under a few categories. 1-Best ride. 2-Best bang for your buck. 3- Eastiest install. 4- Best offroad capability. 5- The best kit in general. I have been told the Bilstien 510 is a great choice but before i pull any triggers i'd like to know all my options as I won't be getting the kit within a month or two as the truck only has 900 miles. Thank you

We are now tuning 2018 GM vehicles. For more information please email us [email protected]

I have a 2018 center console armrest with wireless charging part number 84330208. My parts guy at the Caddy Dealership wasn't paying attention when ordering my console to note that some consoles come with the armrest and some don't. Well he ordered me the console with the armrest and the armrest separate. Since I special order purchased Chevy truck parts from a Caddy dealer I was unable to make a return with out a ridiculous restocking fee. It has never been installed, only removed from the box to take pictures. List price for it is $451.17, Im asking what I paid for it which is $260 plus $15 to ship in the lower 48.

Two easy ways to turn off the engine auto start system in the Chevrolet Silverado 1500 since they do not give you an off switch here's the video link let me know if you have any questions