TwoBallScrewBall

"I don't back up" lolol.....

We have a new 2018 (4 months old) with 4000 miles and my wife just got the "Service Brake Assist" and a hard, pulsating pedal every time she applied the brakes this morning. Turned the truck off then started back up and everything seemed fine. Do they think the 2018's are not affected? We tow a camper with this truck all the time, I don't need to be losing power brakes with ~6000lbs of trailer hooked up and my 2 kids in the back seat. Will be calling the dealer about this later today.

Popped the new CV axle in yesterday. Back on the road.

There were big blobs like you describe on the A-Arms, and on the inside of the wheel barrel. This leak was right near the spindle, maybe that's why most of my mess ended up on the wheel and A-Arms instead of the axle like yours. Some of those blobs on my wheel had 'ran' out the outside of the wheel and onto the face toward the tire, kinda like running paint. I guess from the centrifugal force of the spinning wheel.

Nice clean front wheel on my security camera the morning I dropped the truck off..... I should have taken a photo of the wheel before I cleaned it but I didn't, but there was black grease streaking out between the spokes. Had the truck backed in since we've had it home, we always back it in, but it was pulled in nose first earlier this week from when I had installed some amber marker lights in the grille (that's another thread). So I have some evidence that suggests the puncture and grease leak might have happened at the dealer..... what the hell.....

Can't catch a damn break here. Called all around for a replacement CV boot, nowhere has it aftermarket, GM boot is $88 for the boot, bands and grease. I already have the axle out so I said screw it and dropped the $95 with tax. Turns out the large band clamp does not use the usual ears, but some GM contraption that sits in a vice and compresses the entire solid ring onto the large end of the boot. Of course nobody has it locally. Additionally, there is no way the strut spacers caused this issue, it's a puncture. picture below. Anyway, after determining that this wasn't going back together today, I hit up Rockauto and got the entire damn replacement axle for $88 with tax and shipping, which is $7 less that I got hit for on just the damn boot from GM. Taking that back, prob get hit with a restocking fee. The other local dealer I called also said that GM has been swapping out the entire axle shaft under warranty in cases of boot tears. Which is why they don't have the clamp tool on hand, they have never had to use one. The more I think about this entire experience with this service department (purchasing dealer), the more aggravated I get. They didn't bother even checking where the grease was coming from, just said the boot must have split from the lift blocks. The boot is super soft, its a 2018 with 2500 miles on it, I don't think I could split it if I tried at this point. They also fast talked me into believing that this grease leak was somehow causing the vibration. I am really kind of wondering if they poked the damn boot and then just expected that I would pay for the axle repair out of pocket since they were blaming it on the spacers. That boot is always spinning, I would expect a tear in it if I hit anyting on the road. This is a puncture. The front wheel is also covered in grease, something I am 99.9% sure that was not there when I dropped the truck off or any time before, my wife or I would have noticed. it. The whole experience just leaves a bad feeling. New axle should be here mid week, hopefully done with this after that.

Fixed. Dealer did not fix it. Picked up the truck. Dealer had me under the truck and said the vibration was coming from the front end. Showed me that the driver side CV boot has a split/leak and it's flinging grease, and said that the increased angle with the front lift spacers is causing the vibration and the split boot. Could not argue with him there. Running 3" top-mount spacers. I had read about the stress on the ball joints when running 3" spacers, but I don't off road with it. So I took the risk. Never read anything about CV issues. So I told them I'd address the cracked boot and the axle if needed and pull the spacers, paid my unexpected $80 for the diagnostic (that sucked) and went on my way. Driving home, I get to thinking about the front axles spinning on the highway, and I look down and notice I'm in 4WD AUTO. I flip it back into 2WD and sure as shit, absolutely no more vibration. No shit, wasn't supposed to be in Auto all the time, especially at full throttle at 70mph. So, basically paid $80 to be told I split a CV boot that actually has nothing to do with the vibration I brought it in for. I'm easily at fault here, I left it in auto, I lifted the front end, etc, etc. I do have a bit of a bad taste though about dropping the unexpected $80 and nobody there noticing in 50 mile of test drives that it was in 4wd auto. Again, neither did I until I started thinking about the front of the truck as opposed to the rear, but I'm not a paid tech. Moral of the story, don't stay in 4wd auto.

Got a call from my service writer yesterday afternoon. They had called me on Wednesday morning to let me know that they they thought they might be feeling something, but were not sure because it had started snowing and they couldn't safely hammer the throttle at high speed. I told them to go ahead and keep the truck for a few more days since the weather forecast was good. He confirmed yesterday (Thursday) that they have 45 miles on the truck now and they do feel the vibration at around 70mph, which is a good thing. At least we're past the "can not replicate issue" stage now. He was consulting with his folks within the dealership because they felt that it might have something to do with the lift blocks I have in the rear end. I politely explained that those were the factory lift blocks that come in all those trucks, and he sounded surprised by that which mildly concerned me. I did let them know that I had 3" blocks installed for some time, but removed them and the truck's rear suspension is set up now as it was from the factory. Also let him know that I do have the 3" strut spacers in the front, we both agreed that should not be any concern. If that becomes an issue, I personally don't have a problem temporarily removing them, except for the $80 I'd have to drop on another alignment if I take them out. This was late yesterday afternoon. Waiting on additional updates today.

Dropped it at the dealer last night. Will update on whatever they find.

So current status, rear suspension returned to 100% factory. Front strut spacer blocks still in place. Truck is dead level right now, but I need to tow with it so I do need to bump the back up another inch or two. Even with the rear suspension / pinion angle returned to factory, the vibration is still there. If I floor it from a stop, 1st and 2nd are dead smooth all the way through. When I get to third, pulling through 65mph, the vibration starts abruptly and is there under power, more power = more vibration. If I let off the gas but maintain the same speed, the vibration goes away. Even if I give it about 1/2 throttle so it's accelerating in 4th gear at those speeds in stead of 3rd, vibration is still there. Unless anyone has any other ideas, I suppose I'll let the dealer look at it now that they can't say it's the lift blocks.

2016 lease was up and both the wife and I wanted to upgrade from a double cab to a crew. Good news is we bought this one!! /s

Put the stock blocks back in and removed the leaf clamps, so it's back to 100% factory. Still the same significant vibration anywhere above 65mph with power applied. No change from the 3" blocks to the factory blocks. Wonderful....... 2500 miles and I'm in the mystery vibration club. Should have kept my 2016.....

Clamped the front of the overload springs today. I like the ride better, a bit stiffer but nothing crazy. But no change in the vibration with the clamps, I still have a strong vibration, only under high power and only above 65mph or so. Truck is smooth at any speed at cruise, and smooth under accel until about 65mph, at which time I get a strong vibration, feels like from the rear, until I lift off the gas. Vibration is persistent from 65-85, did not go any faster than that. Next step is to put the stock blocks back in the rear and remove the clamps, and see if I still have the vibration. If so, I might let the dealer take a look at it. If not, then I need to decide where to go from here since I have a 3" level in the front, so I can't leave the rear stock, as it would sit too low. Can we use lift shackles on a 2018 instead of blocks? Wondering if some of the problem is the additional distance between the spring and the axle with the larger blocks, allowing vibration to amplify or resonate / providing more axle leverage on the spring.

Where is the adventure in that???? I'm not ready to be boring just yet. Although I HAVE been told I have old man lights on my truck.... EDIT - excuse me - the wife's truck.

I swapped in the angled blocks I had. 2 Degree I think. Installed so the pinion points more toward the truck, not the ground. Vibration is still there at higher speeds under acceleration, 65-80mph. Might not as bad as with the flat blocks but I'm not sure. I am going to clamp the front of the leafs, I read that helps sometimes. Makes sense, as clamping just the front of the leaf will make it stiffer, as well as give just a bit more upward pinion angle.

Watched video, nothing obvious. Definitely cool to watch the driveshaft and suspension work while driving. Uploading now, I'll share the link in case someone else sees anything I don't once it completes. There is a good 2-gear WOT pull at 4:30, then at 4:55 I merge onto the highway from about 45mph to 80. There was heavy vibration felt in the truck on this 4:55 pull, but I am not seeing much on the video. Definitely coming from the rear, or at least it feels that way. All in the seat, nothing in the steering wheel or pedals.

It's blatantly obvious that the angle from trans to shaft is not the same as the angle from shaft to pinion. Much more angle in the rear joint. Just from eyeballing it, didn't put a gauge on it yet. Just got back from ride, about to plug in USB stick and check video. Going to be towing with this thing in the spring so want to get this worked out.

So we bought this truck new on December 28th. It's got about 2500 miles on it right now. Noticed on the highway this weekend, that the truck has a pretty serious vibration when under heavy load, especially with accelerating on the highway with full throttle. I don't remember this being there earlier than this weekend, however it's my wife's truck and she drives it locally most of the time. And the times I have taken it, I'm honestly not sure if I had ever gone full throttle with it, especially at highway speeds. Only happens under load. Feels very much like an engine miss, but there are no codes, and it does feel more like it's coming from the back of the truck. I have just checked U-joints, no slack and the bolts on the rear pinion straps are all tight. No dents in the driveshaft that I can see. Mods I have done so far that could be related: 3" Front Spacer Lift, 3" rear blocks (in place of the stock 1.25" blocks, and muffler delete with resonator still in place. I used flat blocks, not tapered, after reading about lots of folks having issues with the taper blocks. I do have a set of taper blocks I can throw in to test with. As well as the stock blocks and U bolts. I'm strapping a GoPro to the trans crossmember, facing backwards, to watch the driveshaft and the exhaust when it happens. GoPro is charging right now, haven't touched it in months. Will post back up if I see anything in the video. Kind of feels to me like it could be the exhaust vibrating, and perhaps cutting out that giant heavy stock muffler along with the specific bends my guy put in the straight pipe maybe causing some weird resonance. Or maybe it's just another cursed vibrating Silverado. I had a 2016 Double Cab for 3 years and 25000 miles and it ran smooth as silk from the day I got it to the day I traded it. Kind of miss it right this moment, it might have been a unicorn.

I'm 42. Dont hate on the old man style. And I'll have you know there are 30 side marker lights, 15 on each side.

Bought a bag of 50 of these 3/4" LED marker lights to do my running boards. Had 20 left over. They cost about $0.60 each (bag of 50 of them is $29.99 on Amazon). Wanted to put some Raptor style grille lights on our new Z71. Easy install. removed the plastic trim cover that goes over the radiator/hood latch area, just plastic push pins hold it in place. Then drilled two 1/4" or so holes down from the top of the grille / shroud area down into the top of the grille for a zip tie. placed a 1/4" X 1/2" strip of 3M VHB double sided tape on the LED light and then used the zip tie in combination with the double sided tape to secure the lights to the top of the grille opening as you see in the pics. Ran all 3 grounds together and grounded them on the hood latch bolt. Ran the +12 feed to the trailer fuse (#15 I think) in the fuse box. I like them a bit more spread out than a lot of the other ones you see installed. Very happy with the results.

If that is a dealer installed SC and the truck is being sold as new, the powertrain warranty should be intact and cover it. At least that was what I was told when previously shopping vehicles.

Nothing noticable on mpg or power.

With the cargo light switch off, the cargo light just comes on and off with the reverse lights, which helps with more light when backing up in the dark, and more light when you hit unlock in the dark. The cargo light does whatever the reverse lights are doing. When the reverse lights shut off, so does the cargo light. They do not remain on for an extended period of time. With the cargo light switch on, it also lights up the reverse lights, which is what I wanted in the first place, to help me when arriving/departing a dark camp site, or any other time you might need more light in the back of the truck at night. So if you leave the truck with the cargo lights on, the reverse and cargo lights will stay on for those 10 minutes. I didn't even consider the first option above until I found the posts linked previously in this thread. But I like it, which is why I just used a jumper wire instead of a diode for that connection, so it works both ways.

Thanks all. Got everything wired up yesterday. Ran a diode from the parking lamp circuit (X5-22) to the fogs (X5-10) so they are always on whenever the lights are on. Ran a straight jumper wire from the cargo lights to the backup lights, just like above but a wire instead of a diode, so that they are always on together, whether it be reverse, or with the cargo lamp button activated. Works like a charm. The cargo lights coming on at night with remote unlock is a real nice unexpected touch Thanks again!!