SGI2015

No, these trucks don't all vibrate in spite of what the few that dominate this thread may say. Having followed this topic daily since late in 2014 when I was about to buy a new Chevy or GMC 1500 worries about the vibration issue put those pl;ans on hold. Finally after talking to many, many owners with no vibe problems, and after the dealer let me take the truck home for four days of driving/testing with no obligation, I bought my truck in February 2015. Anything can happen I suppose but 20,000 + trouble free miles later mine is still a smooth vibration-free ride. Out of curiosity I've continued to talk to other owners and over two years of doing so have yet to find one that has the vibration problem. Not saying it's not out there at all, but with over a million of these trucks sold there have to be some lemons. Been there and done that with another manufacturer and it's not fun so I definitely feel for the folks who do have this problem.

Agree, it is a huge turn off, and it also made me very nervous. Here's how I approached it before I decided to buy. When GM began to clear out the 2014's last fall I got very interested in getting a good deal on a Silverado or Sierra. I came real close to getting a nice Silverado Z71 but eventually decided I couldn't live with the color for as long as I usually keep a vehicle. I continued to shop around but couldn't find anything I liked in a 2014 so I decided to wait for the 2015's and, about that time, began following this forum. Like you I got very concerned about all the vibration problems and decided to watch the forum and wait to see if GM could identify and fix the issue. In the meantime, since I still was very interested in the truck, every time I ran across a 2014+ Silverado/Sierra I tried to find and talk to the owners about their experience and satisfaction with the vehicle. Over a period of a couple of months I probably talked to 20+ owners in my area and didn't find any who had vibration problems. I'm sure GM knows how widespread the vibration problems are but considering that something like one million of these new GM trucks have been sold since Jan 2014 to date it's really hard for folks like us to figure this out. I did shop Ram and Ford, I'm sure they are good trucks, but I just never really got excited about any of them. So, eventually in February, after numerous test drives, including taking a Sierra home for three trial days, I purchased a 2015 Sierra All Terrain (5.3 V8, 4X4, 3.42 rear end, 18" wheels, stock Goodyear tires, build date 12/14). While I only have 2200 miles on it so far I have to say I love it. I live in a rural area and don't do a lot of city driving but am averaging right around 20 mpg so far, including two trips of about 400 miles total with a loaded truck and towing a 3500 lb travel trailer. From the experiences of others on the forum whose vibration didn't show up until later I know it's early for me but so far not a hint of any vibration under any road condition or any speed up to around 80. Finally, I'm not saying any of this to make light of the problems folks have had. I feel for the miserable time they're going through because I've been there, done that with GM many years ago (two clutches, three drive shafts, two transfer cases and a year of hassle before a vibration was fixed) and swore I'd never buy another GM product. This time around I just really liked the truck enough to take the plunge, roll the dice, and guess I'm one of the lucky ones.

As others have noted, if the document has been updated for a second time and the document you is have is PIT5374B a lot of Sierra owners would probably like to have a copy. In my case the headlights were successfully updated under PIT5374A and several local Sierra owners I've talked to are also anxious to get it done. I do have a copy of PIT5374A I can share with them but with all the confusion at the dealer level it may not help if PIT5374B is now the applicable bulletin. Can anyone who has just recently had the upgrade done shed any light (sorry) on the question of which PIT is the latest and, hopefully, make a copy available?

Well, after the first failed attempt at the headlight upgrade when the dealer installed a new replacement set of the OEM bulbs I was back today to have the correct bulbs installed, BCM flash and re-aiming. After a short test drive tonight into the National Forest I have to say I am pleased with the significant (and very noticeable) improvement these changes have made. I now have good light ahead on both low and high beams and much better peripheral lighting to the sides. The aim adjustment looks pretty good to me as is but I didn't meet any other vehicles in the woods so I can't say how oncoming drivers will react. I'll probably drive it some more under a variety of traffic conditions and rural/urban settings to get a better feel for how they are adjusted but I may end up following Ranch 55's suggestion to ease the aim up a bit. I think I'll continue to use the fogs when I'm not in developed areas but basically I feel like the lights are now safe and I can enjoy my new truck. Finally, as a new Sierra owner and relative newcomer to this forum, I need to thank all of the owners who pushed and worked for months with GM to make this change happen; also thanks to GM for acknowledging the problem and coming up with a workable fix. I'm late to the party but I am a grateful beneficiary of all the efforts of those folks who refused to let this issue go unresolved.

Thanks for the air box advice. Very helpful. They would have done it today but they were slammed and I didn't feel like spending the whole day there. It was my choice to come back early Monday since I have to be in town for other things anyway that day. The entire thing was very frustrating but I behaved myself and because it was such an obvious series of mistakes I never had to push to get it corrected once it got figured out.

OK, took another 60 mile round trip drive and spent an hour or so at the dealership this morning to try and clear up the issues in my previous two posts. Long story short, yes I did get the wrong (original OEM) bulbs installed yesterday. At the end of it all I would say, given this is a new Service Bulletin that none of them were familiar with until I showed up, that there were layers of understandable miscommunication between the parts and service people about the bulbs and the work that was supposed to be done. Once we got it sorted out the folks involved were both apologetic and somewhat embarrassed. Even more ironic, as I was standing there wrapping up the discussion with the Service Manager and the parts guys an air freight delivery arrived with the correct back ordered bulbs with my name on them. Now I have an appointment on Monday to get it done right. For those folks still waiting to get this done I would say the lesson is to keep a close eye on things so you don't end up like me. With the other issues some have had with things like the new bulbs not being properly seated now I'll be sure sure to follow up carefully to make sure all is good after the work on Monday. Which brings up the question, exactly how do you move or shift the air filter box to get access to the passenger side headlight? Good luck to all!

From the bulb part numbers on the receipt it looks like your replacement bulbs were just like mine - the oem bulbs but not the new part number bulbs identified in the PIT Service Bulletin. If that's true, like me. they just took out the old bulbs and replaced them with exactly the same ones. What a mess..............

Thanks to all who responded so quickly to my post #782 about maybe getting the wrong bulbs installed. Helping folks out is the great thing about this forum. As suggested, pulled the back cover off and the bulb says Phillips - must be OEM. Now I'm wondering if they even bothered to reprogram the BCM. Will have to meet with the Service Manager tomorrow and ask for a complete redo, probably be another week or so on the bulbs.

OK, dealer ordered the bulbs and they were installed today. They got the bulbs installed OK but when I looked at the work order the part number for the bulbs (13587719) was different than the part number in the Service Bulletin (23342527). Then I noticed that there was no mention of reprogramming the BCM or aiming the headlights even though I had them attach a complete copy of PIT5374A to the work order. So, it was back to the shop where they supposedly did the reprogramming and aimed the lights. In the meantime I wandered by parts and asked about the part number change and was told they were unable to order the bulbs under the part number in the Service Bulletin and that, after checking with GMC tech support, learned it had been superseded by the one they installed. Now I'm a bit confused, given that the Service bulletin was updated 10 days ago and now we have a new part number already? Obviously, given the careless work initially done that overlooked the BCM reprogram I'm wondering whether or not I actually got the correct bulbs, or maybe just new bulbs that are the same as the old ones . If anyone who has had the upgrade done recently and has a work order with the bulb part numbers I would really like to know if you guys can help me understand this better. Anyway, test run tonight to see how they look.

Went to my service department today, the bulbs are now on order and an appointment will be scheduled when they come in. Since they had no clue about this issue with the lights it would not have been possible to get anything done without a copy of the TSB/PI, which ever it is, that was available on this forum. Handing them a copy got the ball rolling. I'm new to the forum and my truck is now only three weeks old but I was totally spooked by the pitiful headlights lights from the very first night's drive. I feel very sorry for all the folks who have suffered with this and tussled with GMC for a long time to get this resolved. As the new to the party beneficiary of all the hard work of so many people on the forum I just have to say thanks to everyone who made this happen and,I guess, thanks to GM for stepping up and offering a fix. Looking forward to being able to drive (safely) at night.

Thanks so much for the pdf file. Hope to see the dealer tomorrow and have better luck getting them to respond with the TSB in hand than I did on the phone.

Thanks. Not the best copy but I did finally figure out how to print from the jpg pictures. I just needed something to show my unresponsive dealer and this should work ok. I'm going to visit with the service manager tomorrow, show him the TSB and see if that gets things moving.

Ranch55 - all of your posts, and especially the pictures, have been tremendously helpful to those of us who have been struggling with the headlight issue. In my case the truck is only a couple of weeks old but the first evening I drove it, almost whacking a pedestrian "hiding" on the right side right next to the truck as it went by and then running off the road toward my neighbor's pasture making a sharp (90+ degrees) turn from a two track dirt road onto the (also dirt) road to my place, I was stunned by how dim the lights were and how limited the peripheral lighted area was. I've made that right turn thousands of times and I literally could not tell exactly where I was on a black dark night with no peripheral illumination. I complained to the dealer immediately and they wanted me to bring it in to check the alignment which didn't seem to me to be the problem at all. Then the TSB came out and since my truck is a December 14 build and I definitely lived in a dark rural area I'm eligible for the upgrade. Called my dealer, they were not aware of the TSB, gave them the number and they were going to get back to me. Still waiting. In the meantime I have, after multiple tries, failed to be able to print the pictures of the TSB posted earlier so if anyone has any suggestions about how this can be done or if anyone has a copy of the TSB that could be posted as a pdf that would be very helpful. I feel bad for those of you who have struggled with this for the long time it has taken to get this resolved but I'm extremely glad that GM has addressed this issue and happy that the result seems to be good. Can't wait to get mine done so I can drive at night - otherwise the truck has been great so far.

Thank you very much. That is very helpful and clears up who's eligible. Based on other posts I'm assuming other parts of TSB address new bulbs and aiming the lights?

Well, I'm confused but hopeful. Looking over the VIN decoder found elsewhere on the forum the 10th position is the model year (F, which I have, is 2015) and the 11th position is the build plant location, for my Double Cab it's Z for Ft. Wayne. The location identifier for Crew Cabs built in Mexico in the 11th position is G. Not an expert by any means but it appears the only way to refine the date further would be by the consecutive sequence numbers - the last six numbers in the VIN. Because of the holidays I would be very surprised if any trucks were built after December 24th until sometime in early January. So, I'm definitely looking forward to hearing what you learn from the dealer tomorrow.