Our 2017 2WD Colorado Z71 with 33k miles started making a knocking sound at low speed, worst at around 20mph, sometimes more noticeable than others. First the dealer put it down to normal tire noise, then a few months later when the noise got worse said it was cupped tires and that we needed to replace them. They recommended less aggressive tires as the "stock" all terrain tires always cup and make noise apparently. So, we had a new set of tires put on and the rhythmic thumping was still there, more obvious now that it wasn't masked by tire noise. The noise seemed to come from the front of the car and was noticeable at low speed 10-20mph and would speed and slow with the car. Once you're tuned into it you can hear it/feel it around 40mph too but its more of a vibration.
Took it back to the dealer and test drove, they heard the knocking and decided to replace both front hubs under warranty. When we picked the car up they said the noise was gone other than normal truck noises, on the drive home it obviously wasn't. In fact it's worse under some conditions.
Now it seems that either the problem is getting worse or we're hearing/feeling things that aren't there. The knocking has become stronger but only sometimes, and at highway speeds it feels like the whole truck is buffeting and vibrating. It also seems to be slipping gears, or shuddering between changes at low revs.
Having taken it back tot he dealer they say there's nothing wrong, they can't hear or feel any problems, and to be fair to them the knocking was less noticeable when I drove it with them but the vibration and shudder was there. I did ask to drive a new one so I could feel the difference and perhaps it's just normal but they didn't want to do that.
I've now left it with them and asked them to test drive it more and if they're happy there's no problem then I'll pick it up and if it comes back I'll take it somewhere else for an independent test.
We're 100% sure on the rhythmic knocking/thumping, especially as it's the same issue before and after the tires and hubs were changed, perhaps this is normal. As for the vibration and buffeting we're less sure, it does seem like it's slipping gears and shuddering but after so much focus listening to the thumping perhaps we're just seeing problems where none exist.
Does anyone else have any similar experiences, or are we truly just going a bit nuts?
January 23rd, 2019
There were good, and less-good things about the 2019 North American International Auto Show. It was smaller than the last few years as, generally, European and premium luxury manufacturers made other marketing decisions. This, of course, left open space which Cadillac, Chevrolet and GMC, as well as Ford and FCA used to their advantage. Chevrolet, in particular, had an enormous family-friendly display of trucks. Oh, and some cars. Cadillac had its first bi-level display, with the upstairs reserved for dealer meetings and journalist interviews. GMC’s floor space swept from one aisle to the next, a linear flow of trucks and SUV/CUVS.
We had an opportunity to talk with representatives of each brand about plans for 2019, starting with Silverado’s chief engineer.
Tim Herrick, executive chief engineer for full-size trucks at GM
As background, GM and Chevrolet have recently introduced the 2.7-liter turbocharged I-4 for trucks, the 2.8-liter diesel in Colorado, a 3.0-liter inline six-cylinder, and a no-details gas engine for the Heavy Duty trucks we’ll tell you about early in February.
Our first question to Tim was about the 3.0L diesel, which appears late in the spring. “It’s aimed at both fuel economy and great towing capability. The diesel will be heavier than the 2.7L; it has the whole chemical factory added on and, as I’m driving it now, overall your impression will be it’s super responsive. I love it. You will see it soon; let's say second quarter. Get the government open; I can't post my numbers until then, I'm ready to go!” Tim exclaimed.
Tim segued to the 2.7L. “Did you drive the new 2.7 gas engine (yes, we did)? I smile every time I drive it; it's lighter than the other engines, the twin-volute turbo is super-responsive, it spools up fast and it’s fun off the line, nimble.” So some of the nimble is the suspension calibration, we asked? “It’s the overall architecture, when you take 450 pounds out, you can put it back into the fun-to-drive. It's the best driving truck we've ever produced.”
With RAM posting record sales numbers we asked if the truck aspect of Chevrolet is fully fleshed out, if there was room for a mini-truck or truck/CUV?
“It doesn't feel like it. We have a four-truck strategy with Colorado, Silverado, Silverado HD and medium-duty. We're happy, proud of our strategy and we sold over a million last year.”
It's interesting that the previous Silverado, now over five years old, was said to be too conservative, and now "they've gone too far", for instance the hot-button over rounded wheel wells versus squared. Truck customers are conservative and don't welcome change, even though they demand it.
“When you examine the whole franchise of the company, it's a marathon, not a sprint. Maybe it's an Ironman! You're just seeing the tip of the iceberg, for instance the Heavy Duty program, and more to come.” What you may not know is that Chevrolet just got to a 50/50 production split between the old truck, K2, and the new truck this month, January 2019. Dealers are just reaching their own 50-percent of new trucks delivered.
Tim is extremely proud of the truck and its architecture; this is the largest program General Motors has ever done as it underpins Silverado, Sierra, and both large SUVs. “We'll make more news in 2019 than any other truck company,” Tim said.
We turned to customer perceptions and needs. For instance, a 2019 Silverado LT 6.2L we had for photography was, on the exterior, exemplary. On the inside it seemed oriented towards hard- core truck buyers with large, and plain buttons; no glitter. It was entirely about "I've got gloves on and my truck and I work for a living." We asked how these interiors would play versus the competition?
In answer, Chevrolet says the vast majority of sales are to Chevy truck loyalists, people who have been Chevy truck owners their entire lives, and are incredibly important to reach and satisfy. Much of the growth in the truck segment is from segment-switchers making their first truck purchase. They have similar needs and wants as lifelong truck buyers, according to the exec.
“Customers are at the core of everything we do,” Tim informed us. “We had over 7,000 respondents to our new Silverado truck clinics. When the numbers were summed, we delivered on what the numbers said for exterior and interior. Customer feedback was great.
When we took the new truck to clinics and talked to our customers, and yeah, they do wear gloves and they do work hard. They do have expectations; the biggest is that the interior holds up for the life of the truck. Whether that's a three-year lease or six-year note, it's got to look as good on the last day as the day they bought it. The quality and durability of our materials—we have real aluminum—a great layout for functionality that is soft where it needs to be soft. We gave a great lineup in our infotainment systems (8" screen in the center) and the largest HUD (Heads Up Display) in the industry—it's three-inches by seven and you can parse your information. You can put your directions up here, your stereo over there and your speed over here. You get the information you want in three spots. We find that's a great solution for us.
When we took the materials to the clinic and talked to customers—they're a working bunch that buys things for value—they loved it. We have seen the competition, and some of the luxury they've brought in. We're not sure it will stand the test of time.”
We asked if there is a known stake in the ground where massive changes occur? "I don't know,” Tim continued, “I don't see that (elimination of IC engines) happens. A truck has to do everything. It has to be quiet and comfortable, it has to get good fuel economy on the highway at 80 mph, and it has to tow and haul; it’s the broadest use-range of any vehicle, while meeting government standards. The one that wins is the one that best integrates ride-and-handling, quietness, comfort, technology, usefulness, tow and haul and great fuel economy, while looking great.
Chevrolet’s display broke into segments related to vehicles and technology, for instance Silverado, Colorado, the SUVs and a virtual-reality race. Each had it’s own display space and theme. What we found amazing, and not in a good way, was the color choice for the trucks on the main Silverado display space. While earth tones are all the rage in urban environments, on the stage, well, look for yourself (we’ve included Silverado exterior color chips for comparison). The Silverado simply disappears despite thousands of Watts of illumination. Contrast that with Colorado’s display.
GMC trucks and full-sized SUVs
We next spoke to Stewart (Stu) Pierce, senior marketing manager GMC truck and full-sized SUV. Having participated in the AT4 launch prior to the 2018 Auto Show New York, we were somewhat up to speed with GMC’s recent actions.
Our question to Stu was obviously about their plans for 2019. “The big thing is the all-new next-generation Sierra,’ Stu said “though it was introduced several months ago. So far the reaction is enthusiastic, particularly for Denali and the new AT4. The AT4 has been the biggest surprise, as we expected it to be 10-percent of total sales. In fact, orders are coming in around 20-30-percent. Our only problem is fulfilling orders, which is a good problem.
The cool thing about the AT4, and why I think its taken off so well is, there were no direct competitors. Every brand has off road trucks; a significant portion of truck buyers want off-road capability. Nobody has done a premium off-road truck. (Ford's Raptor and King Ranch, RAMs Laramie Longhorn would seem to fall into similar categories, however. ED) Sort of, if you take a rugged off road truck and blend it with Denali, you get AT4.
AT4 has extremely high levels of refinement and technology, and performance from the 6.2L engine. It's got a 2-inch lift, all the off road parts including Rancho shocks, skid plates, recovery tow hooks, Hill Decent control, dual exhaust, LED headlights, locking differential and more. It's been the biggest surprise to us.
Beyond that, the technology we have like the rear camera (with 360° and tow-hook views) and HUD, all have been super-well received. As these trucks become stronger appearing with a big, tall hood and big, tall grille and bold truck appearance, at the same time, you've now got the ability to see all around you so you can park where you need to. It looks great, gives you the kind of presence and image you're looking for, and at the same time its easy to use, easy to drive.
I think the biggest GMC truck feature is the MultiPro tailgate, a world's first. Nobody has anything like it. I've been at the show for two or three hours and there’s a constant stream of people coming from other brands, and journalists wanting to look at the MultiPro tailgate. It's got six functions (tailgate, load stop, foldable inner gate for access, full-width step, Inner gate second-tier load stop, inner gate work surface, Ed.) and it's the feature that dealers say customers who would never set foot into a GMC store stop in to see. And it's standard on more than 80-percent of 2019 trucks—all Denali, AT4 and SLT levels.”
Having covered the Sierra, we wondered what else might be interesting in 2019.
“We've released some new packages for Yukon, a new Graphite Edition in two versions, Regular based on SLT with chrome trim removed and a unique grille and wheels, the other version is Graphite Performance. It has the 6.2-liter. So, you can get a blacked-out SLT with great driving and great power. You also pick up things like magnetic ride control, previously unavailable, and a Head Up Display.
We've also got the Yukon SLT Standard Edition, sort of value proposition; it enables someone to get a leather interior, not necessarily the other bells and whistles, at a more affordable price. We're running the plant at full overtime.
Terrain is doing well, and to go back to Sierra, we have a new Elevation model which started production in October 2018. Dealers started receiving them 30-45 days ago. It's our new double-cab on the next generation truck platform. Like the Crew Cab, it’s larger and roomier than the truck it replaces. There’s greater knee room, a 6.6-inch bed and the 2.7-liter turbocharged engine is standard. It's monochrome, with 20-inch painted wheels. And it's a bit more affordable without stepping up to the fully loaded trucks.”
At GMC the "stay tuned" message was about the 3-liter diesel and carbon fiber box, which will arrive soon and debut on Denali and AT4.
GMC’s display feature a new Heavy Duty track concept with no production intent. It’s for you to buy, and compared to SNO-CATs, is far less expensive. GMC added it to celebrate their partnership with Vail, Colorado. Overall, the GMC display was bright, cheery, and sophisticated in its simplicity. Yeah, we’d call it Professional Grade.
Cadillac's all-new XT6 three-row CUV
Cadillac held an offsite introduction for new product the day prior to NAIAS. We were not invited. The biggest news, other than the 2020 XT6, was a visual-only display of Cadillac’s first full-electric vehicle. Cadillac, as GM’s luxury brand, will receive GM’s first future EV platform model. The platform will, as it must, be flexible and configurable (batteries and e-motors) in front-, rear-, or all-wheel drive. Battery systems will be based on “vehicle and customer needs”.
“Cadillac’s EV will hit the heart of the crossover market and meet the needs of customers around the world,” said Steve Carlisle, president of Cadillac. “It will represent the height of luxury and innovation while positioning Cadillac as the pinnacle of mobility.”
Nothing more was shared, though continuation of Escalade and an upcoming performance sedan were hinted. In a bad pun, we think Cadillac must electrify their game. BMW’s announced i4 and iX3, Mercedes EQ brand and announced EQC, Jaguar’s available-now I-PACE, VOLVO’s 2019 SC40 CUV and other BEVs (battery electric vehicles) make speed-to-market a necessity.
After I received the business card from marketing project manager Cadillac XT6, James Hunter, we began our chat about Cadillac's latest SUV, the 2020 XT6. While not mentioned, the XT6 is based on the crossovers built by Lansing, Michigan's Delta Township and Springhill, Tennessee facilities, Buick Enclave, Chevrolet Traverse, and my research says it's closest in size to the GMC Acadia. Springhill also builds the XT5.
"XT6 is all-new, and Cadillac's mid-sized luxury crossover," Mr. Hunter said." It fills a void in Cadillac's portfolio, which is flanked on one side by the (two-row, 4-5 passenger, Ed.) XT5 and the other by Escalade. It's for customers who have need for additional cargo/passenger flexibility. You might carry 6-7 passengers, or fold everything flat for 78.7 cubic feet of cargo (43.1 cubes behind the second row, 12.6 if configured for three passenger rows, Ed.) It will tow 4,000 pounds with the tow package that delivers Guide View for the hitch."
We asked if this was an alternative to Escalade? "Sliding XT6 between Escalade and XT5 offers passenger capacity, providing an alternative to customers who don't need a body-on-frame truck. It's a more modern-feeling vehicle, with Cadillac's most modern technology. For example, Infotainment-3.5 and its rotary controller with a jog feature to scroll and navigate more easily. We do maintain steering wheel controls, and at the same time hard buttons and touch-screen options to provide choices. Another example is our family of instrument clusters; they are larger, with higher resolution. We offer a Heads Up Display in our Visibility Display Package that comes with a 360° camera, advanced park assist, pedestrian detection; complementary technologies."
Packaging features and options for manufacturing simplicity may not offer the best customer-oriented solution. "We spend a lot of time optimizing packages, leveraging our portfolio and all of our brand’s experience and history. I think we hit the bull’s-eye!"
Beyond XT6, what does Cadillac have to provide excitement this year, to an increasingly young customer? "There's the Escalade Sport Package for 2019, and some other things I'm not at liberty to discuss. The 2020 XT6 starts production soon, and vehicles will arrive late in 2Q, early 3Q. The 500+ horsepower CT6 V-8 will arrive in a similar time-frame."
We asked about the changeover from sedan-heavy to SUV/CUV-rich. "I think we have a very good start with the current lineup and the addition of XT6 and XT4, plus the higher-capacity Escalade ESV provide a broad range of customer appeal as customers move through various life stages. We are, of course, monitoring the competition." We asked about an XT2, even XT1 small crossover, as these are very hot for Buick, BMW and others. "Going forward, we'll be exploring the needs of customers," which was about the answer we expected. "We recognize that we needed to improve our average age in the marketplace. We didn't have a range of products that appealed to a younger, active lifestyle. With the XT4 and XT6, we expect a reduction in average age as we meet the needs of 40-50-year old buyers." That's good for everyone, as the saying goes, "You can sell an old man a young man's car...'"
“Not only are we delivering product to appeal to a younger customer,” Hunter continued, “We are providing trim levels for their tastes. An example, the XT6 offers a Premium Luxury model calibrated for more isolation, or Sport models with active suspension and faster steering for a more responsive ride."
Cadillac’s display was, as expected, a bit brighter, a bit more upscale with a raised platform for its all-new 2020 Cadillac XT6. That XT6 was colored in what I think General James Mattis might receive as a gold watch substitute. It’s OD Green, rather than a compelling color like copper, or red, or blue, or white, or black or almost any other color. Cadillac, featuring a drab, dingy, lackluster color for your new flagship product in your hometown display? Shame on you!
I have a set of 2019 Chevy Colorado rims that are 18x8.5 and 6x120 and they come with tpms already installed. These will fit any 15-19 Colorado and the tpms just need to be programmed to the vehicle. MSRP on these rims and sensors are $2310.08 before tax and core charge (which is $50 per rim). I'm looking for $1600 obo they do not come with tires or center caps. Message me if you have any questions. I have more pictures of the back of the rims showing they are genuine GM rims but they are to large of a file to upload.
Contributing Writer, GM-Trucks.com
December 6, 2018
Last month Chevrolet invited us to test the Chevrolet Bison, a ZR2 derivative with distinctive upgrades that add to its already solid off road capabilities.
Built off the already-capable Z7R2, American Expedition Vehicles (AEV) provided the collaborative additions that created Bison. It retains the class-exclusive front and rear locking differentials from ZR2, and high-zoot Multimatic DSSV dampers. The design of the Dynamic Suspensions Spool Valve dampers uses hollow cylindrical sleeves instead of familiar discs. These were used first on race cars including Champ cars, LeMans prototypes and F1 They provide superb off road damping, particularly on rough trails where they offer greater passenger comfort.
Getting to the grit of it, a pickup is hard-pressed to have the approach angle of a Jeep, and impossible for a production bed to provide a really short departure. Nonetheless, Bison does a very good job of going over rocks. One of the AEV additions is a set of five hot-stamped Boron-steel skid plates to protect the oil pan, fuel tank, transfer case and front and rear locking differentials, which we tested extensively. “As this is the first Chevrolet vehicle we’ve given the AEV treatment to,” said Dave Harriton, founder and president of AEV, “we wanted to do something special with the industry’s first use of hot-stamped Boron steel.” We think he’s referring to the off-road industry, as hot stamped High Strength Steel is the basis for modern crash-worthy chassis. However, those skid plates kept the rocks out of our oil pan.
Some of the Bison upgrades are more cosmetic than necessary, like replacing the bowtie grille a free-flowing CHEVROLET front grille, Bison decals on the bedsides and an AEV Bison logo on the tailgate plus an embroidered AEV on the floor liners and front head rests. Branding, eh? Performance-oriented changes include the stamped steel front and rear bumpers. The front bumper allows adding a winch (would you go off roading without a winch??), fog lamps and integrated recovery points.
As a truck designed to venture deep into open spaces, Chevy added 31-inch Goodyear Wrangler Duratrac tires mounted on Bison-specific 12x8-inch aluminum wheels. We tested those, too, and they have plenty of grip on rocks, and in loose dirt. Note that the ZR2 cast-iron control arms and Autotrac transfer case are retained, along with the ZR2’s 3.42:1 axle ratio and front/rear tracks wider by 3.5-inches. Compared to a ZR1, Bison is lifted by two-inches.
Our test vehicle was powered by the new 2.8-liter Duramax diesel (186 hp., 369 lb.-ft.) mated to a six-speed transmission. It was the crew cab model; with the short bed which including some AEV upgrades.
On our highway drive towards an off-road park, we noted that the Bison was extremely quiet, and not just “quiet, for a truck”. No, it was quiet for any kind of vehicle, including a Cadillac. After switching the transfer case into 4WD-high, we bucked our way towards the promised bigger challenges. Along our trail—nothing extreme but way off the beaten path—we again noted there hadn’t been a single squeak, rattle, or buzz. The only odd sounds in the cabin were from the zippers on our camera bags. Bison’s frame is stiff; there’s no tweaking, everything is absolutely tight.
There was no way to call out the suspension and its Multimatic spool-valve-type dampers, however the suspension was supple on the rough trail. Another noise-related note, we picked up no rock noise in the wheel wells despite being pushed around by potholes, rocks and dips. We might as well have been on the freeway, from a noise perspective.
Our truck had almost every American Expedition accessory available. There were LED fog or trail-search lights on the hood, a ladder rack and a storage bin system mounted below a false bed. We only lacked the Baja-style intake snorkel.
The bolted-on roof rack may have added stiffness to the already ultra-stiff box frame, which allowed the suspension do its work. Watching the vehicles ahead of us, we could see how steady the beds were, and how much the suspension was working. For a stock vehicle, there was plenty of travel available. Bison has a solid rear axle and independent front suspension, and there is a divide among off roaders and rock climbers as to whether a solid axle or independent rear suspension is better. Rock climbers seem to prefer solid rear axles.
We thought the ZR2-based Bison chassis with a Duramax diesel made off roading almost a no-challenge event. The diesel engine was totally on-point with torque, needing only a light application of brakes for stability when balancing on rocks. Comparatively, those who had the standard V-6 gasser had a harder time of it, using more throttle to obtain torque, then having to feather the throttle and brake to stay on track. If you've never done rock crawling, you must apply power to get up, apply brake to stop, before being guided down in the correct direction. Yeah, it's really hard to see the front wheels through the engine.
One of the options Chevy will offer through dealers is a shorter, cut off exhaust tip. We strongly recommend this if you’re going rock crawling. Many of us “modified” the longer exhaust tips when crawling off rocks.
After crawling a rock canyon we grouped to head for lunch. Parked on a hill with loose sand and the tranny set in 4WD high, there wasn't enough traction. Locking the rear differential made climbing the hill as simple as stepping on the throttle, in that low traction situation. Having complete control over axles and each wheel made off roading and rock crawling easy, even for beginners.
Note that, in our opinion, the Duramax doesn't deliver optimum fuel economy for the Bison. It's good, but not great. Where it shines is in torque availability for off roading. We can see the Bison with Duramax as a perfect combination for off road camping, adventuring, and modest towing. It's quiet. While on our rock crawls, there was never a sound from the chassis, no wracking, graunching, squeaks or rattles other than when we skidded over rock on those Boron steel protectors. It was billet solid. In fact, we'd go so far as to say our Bison was quieter than a standard Silverado and totally ready for any off road adventure.
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