I agree that the 1 MPG difference caused by the Range device is totally insignificant. I have done the calculations and a Tundra would cost me about an extra $600 per year in gas. My wife and I pay cash for our vehicles, so that isn't likely to break us in the near future. However, as an engineer, I don't like using something woefully inefficient when other options are available without compromise. If I were really concerned about fuel economy, I would buy a Tesla Model X instead of a big pickup truck. That being said, my problem with the Tundra is the fact that is based upon 2005 technology. While I applaud its reliability, I can get 17 mpg mixed and 20 mpg highway on my GMC with the Range device turned on. That's basically an apples-to-apples comparison because they are both similar sized V8s with 6-speed transmissions. Toyota also has very strange options--I like the looks of the TRD Sport package, but you cannot get that package on a Limited or Platinum truck. The only high-end truck with that package is the TRD Pro that doesn't even have automatic climate control. The Tundra has a 4.30 axle ratio and there appears to be no other option--both of my gas guzzling classic Chevrolet cars have smaller ratios and probably get about the same fuel economy (well, probably not the 396). My '99 Dodge got 11 mpg mixed and 15 mpg highway--I had to visit the gas station 2-3 times per week. I got a little tired of that. The Tundra isn't much of an improvement. In short, I like the looks of the GMC trucks, but I am tired of paying lots of money to be a beta tester for the General (that's why I bought the SLE this time--it had the 6-speed instead of the 8-speed transmission). I want something that doesn't make me visit the gas station every third day and the service department every month or two. I'm hoping the DFM will be reliable because it looks like that is going to be the future of GM engines. I just don't want another truck that bucks, lugs, and slams its way down the road.
Good advice. I test drove a Nissan Titan and loved it--it ran like a frightened deer and it drove really well. However, I have a friend who works for an automotive supplier and he recommended avoiding the Titan. He showed me pictures of a few parts on Internet automotive supply websites as examples and I can't fault his logic. Almost all of the Titan reviews I have read online (professional and owner reviews) have been mediocre at best. It's sad, because they are nice trucks. I have looked at Tundras, but they drive like an enormous vehicle (I'm 6'3", so it says a lot when I think something seems huge). Also, I have talked to Tundra owners at gas stations and they all claim to get about 13 mpg. That's a little painful because my '14 GMC regularly pulls 18-20+ on my commute. I am a previous Ford Ranger owner and a previous Dodge truck owner. They were both OK. However, the owners of new Fords at work have had horrible problems with them (cracked oil pans, timing chain issues, turbo issues, transmission issues) at very low mileages (10-30K). I like the look of the new Dodge trucks, but my automotive supplier friend also very strongly advised me to avoid FCA products. My daughters both have Mazdas and they have been almost flawless after years of faithful service. I wish Mazda made trucks. I will just stick with my GMC until the extended warranty expires. If it is still doing OK, I may tune it to get rid of its spastic behavior. I just don't relish the thought of paying $2K to fix the likely A/C failure. On my last GM product, the first failure (4WD issues and water pump at 31K) was quickly followed by the second, third, fourth, and many more. I won't go down that path again.
Thanks for the reply. I visited the dealership today and test drove two different SLT premium trucks with the 5.3 and 10-speed transmission. They drove very nicely. About a month ago, my salesman gave me a verbal trade-in estimate for my truck that was right in line with the KBB trade-in value, so I thought it would be worth investigating the cost delta to a new one. Of course, the dealership offered me much less than the verbal estimate today, so I am going to stick with my truck for the time being--it's pristine and still under warranty, so why not? I still have very serious reservations about buying another GM after the "bait and switch" routine the AFM system pulled on me with this truck. I would want to be assured that the new truck drives the same way after time passes.
I am getting close to the end of the extended warranty on my 14 SLE Z71 crew cab. The truck has not had any major problems, but I have not been a fan of the AFM system. Specifically, after about a year, the truck slowly started driving totally differently than it did when it was new. It went through the "clunk" and "slam" phase, then the AFM became more and more aggressive until it now tries to kick in all the time. I get really sick of the "lug", "lurch", "lug", "lurch" during the lower speed portion of my commute. The service department says the ECU has "learned" my driving situation and has adapted to it. I really want it to "unlearn" my scenario, but resetting the transmission learning doesn't seem to affect the AFM behavior. I have a Range device, which helps significantly, but it definitely affects my fuel economy (down about 1.x mpg). When I talk to my salesman, he says the newer trucks with DFM and the 10-speed transmission do not exhibit this behavior. I would like to hear from people who have these trucks to see if that is true. There are some really good sales going on right now, even on 2020 models, so I am tempted to upgrade to an SLT+ truck while my truck still has a good trade-in value. However, I don't really want to buy another "Jekyll and Hyde" truck that will totally change its personality as it ages. Can any 2019 owners with DFM and a 10-speed transmission comment on how your truck is doing after a year?
I have a 2014 GMC SLE and live in Southern Ohio. I wash the underside of my truck after every salt application as soon as the temperature gets near or above the point where the water doesn't flash freeze. I have to go under the truck every summer with a wire brush and cans of Rust-oleum and spray undercoating. My wife thought I was crazy until I came inside with a large handful of flaking wax and told her that was the stuff protecting the frame of the truck. I asked the dealer about the problem at an oil change--they told me that GM has offered no suggestions other than re-waxing the frame at the cost of about $1K. If it works as well as the factory stuff, it would NOT be worth the effort. My wife is encouraging me to look at other manufacturers when I replace the truck. She is wise.
I totally agree that the tuning is likely to fix the truck--even some dealership service personnel told me it will make the truck run better. However, I have an 84 month/84K mile extended warranty, so they strongly recommend waiting to get it tuned until the warranty has expired in case something happens in the meantime. I'm using the Range Technology device, which makes the truck far more tolerable. However, I just wonder why it isn't possible to get the truck back to the way it was when it was new--it ran well and the AFM wasn't objectionable. I would love to have that truck back! BTW, my truck is bone stock--no larger tires or anything else. Other than new tires at 50K, nothing has changed since new except for time, mileage (60K now), and maintenance.
I really envy those of you who get 200K miles from your GMs. I have gotten nearly 200K miles from older imports, but never a GM. I do use fuel cleaner (Chevron Techron) at regular intervals. I have my transmission fluid changed at 40-50K intervals and my coolant changed at around 50K intervals (both are done professionally, usually at dealerships). My oil is changed at 3K (mineral) or 5K (synthetic) intervals. I have always done it myself (which is how I discovered many of the leaks underneath a vehicle) but now the dealer does it cheaper than I can do it, so I let them. Here is our list of woes: 1992 Achieva SC, which was my wife's (then girlfriend's) first new car. Engine had low oil pressure when I drove it at 500 miles, so we took it to dealer, who said it was OK. Engine threw a rod at 900 miles. She got a new car, which had a bad dash cluster when she drove it off the lot. It ate coil pack housings and it ate a water pump before 50K miles. At around 60K, the dash cluster failed again. At 75K, we needed a bigger car due to the family growing and no dealer would take the Achieva on trade due to the engine's reputation. We basically gave it to a coworker at wholesale. Next, 1997 Chevrolet K1500 extended cab. First model year with third door, which was hung incorrectly and never closed properly. Several dealerships tried to fix it but could never get it right. Alignment issue on day #1 and an injector failed at a few thousand miles. I had the rear differential fluid changed at 1K miles per recommendation (with friction modifier), but the rear end was making noise at 31K miles. Since the warranty was about up, I traded it. I can't remember if it ate a water pump, but I'm thinking it might have. I remember taking it to the dealership quite a few times because they could never make things right. The Achieva was replaced with a 1998 Pontiac Montana. It was actually pretty decent, but I believe it still ate a water pump by 50K. We sold it at 58K to get a nicer 2003 Olds Silhouette. That van was very nice but it had a head gasket leak at 35K miles. The rear wheel bearings failed on a trip at 65K miles. It ate rear lamp holder buckets for lunch. Next, my 2004 Tahoe Z-71. An electrical issue when new would drain the battery if it sat for more than a few days without being run. At around 31K, a front axle seal and the water pump started leaking. At 35K, the shift encoder motor failed. All driveline fluids were changed by the dealer at 50K (front to rear)--they thought I was crazy to do that. Front wheel bearings failed at 70K and the rear wiring harness corroded at the rear junction box. In the 90's, the instrument cluster failed and the Castech heads cracked at 100K, so I installed a Jasper rebuilt engine. At 110K, the fuel sending unit failed, requiring an expensive flex-fuel pump. At 120k, the transmission developed a 2-3 shift flare (allegedly common), requiring the transmission to be rebuilt. In the 130s, the brake lines were dying and the HVAC controls (front passenger and rear) were periodically malfunctioning, so I traded it in on the Sierra. The 2003 Silhoutte was replaced with a 2009 Acadia SLT. This truck wasn't bad, but it had multiple electric steering issues and it ate a water pump before the first 50K change. We traded it at 89K because everyone we knew with a similar Acadia had a timing chain failure at somewhere around 100k miles. My wife now has a 2015 RAV4 Limited AWD, which has had zero problems in 56K miles. My 2014 Sierra has actually been pretty good except for the clunk/lug/slam of the AFM system. It actually made it to 50K with the original water pump, which seems to be a minor miracle. However, I really don't enjoy driving it, so it will probably go bye-bye when the 84/84K warranty is about to expire (I'm not going to put a $1K+ A/C system in it--I installed the bracket, but I don't know if that will keep it from failing. So, those of you who get 200K miles from your GMs, I salute you. We have a 1991 Mitsubishi 3000GT with 175K miles that I drive daily during the summer--there are days I trust it more than my truck.
I totally understand your situation--good luck in getting to 150k miles. My wife is a Michigander who was raised in a GM family, so we have owned seven new GMs (cars, minivans, trucks, SUVs) since 1992. Despite following maintenance recommendations to the letter, we have never gotten more than 50k miles without losing an engine (early Quad-4 blew at 1K miles), head gasket (3.4L at 30k), or water pump on any GM prior to my current pickup. In fact, I almost forgot to have the coolant in my truck changed at 50k miles because I have NEVER had to do it before--it has always been changed with the water pump every 30-40K miles. I loved my last vehicle (2004 Tahoe Z-71), but the Castech heads cracked at 100K miles and the transmission got a 2-3 shift flare at 120k. This was in addition to the fuel pump, gauge cluster, 4WD shift motor, front wheel bearings, etc. that failed before 120K miles. Honestly, I will probably trade the truck before my extended warranty expires--I'm not going to sink $10k into this truck like I did with the Tahoe. I actually test drove a used Toyota Tundra before buying the GMC--it was several years old, had 40k miles, and cost more than the new GMC. By the way, my wife now drives a Toyota and she loves it. So far, 56k trouble-free miles.
If that actually works, you will be my hero forever (or at least until I get another vehicle). One question--how is this different than pulling the battery cable? The dealership pulled the battery cable while they were changing the oil not long after I started complaining about the problem. For the first 100 miles or so, the truck was pretty spastic as it relearned its fuel maps, but then it went right back to aggressively activating AFM. That was during the "clunk" era, as I recall. I hear you about the adaptive transmissions being awful. I have no idea what vehicle I will get next--I have begun to start thinking about it since I only have two years of extended warranty left. As an engineer, I hate seeing needless features being stuffed into vehicles nowadays. It really makes me wish I could move to some part of the country where I could drive my old cars all the time. Are there any trucks that get fairly reasonable mileage and don't have all of the emissions/fuel economy garbage? At least the current truck doesn't have auto stop/start--I couldn't handle that, especially since you cannot disable it on GM vehicles. Thanks for the advice--I can't wait to see what happens! I can pull the fuses regularly if it makes the truck decent to drive again.
Thanks for the suggestions regarding the higher octane fuel--I will try a tank of higher octane fuel and see what happens. Even though the truck doesn't get terrible fuel economy overall, I don't relish the thought of paying $0.60 extra per gallon every fill-up. I have to wonder why the truck did so well for the first year or 10K miles (more or less) running on 87 octane fuel--does it really take that long for the system to adapt to your driving habits???
Thanks for the information about the TSB. Unfortunately, I have the six speed transmission and I had it flushed at about 50K miles. I did not notice any difference in the behavior. I have been privately told by service folks to be glad that I have the six speed instead of the eight speed transmission. The weather is staying warmer now, so the problem is much less noticeable overall. What really puzzles me is why the truck was really good for the first 10K miles (more or less). I bought it in October of 2014, so my first few months of owning it took me into the colder weather months. Does GM dial up the aggressiveness of the fuel economy measures over time so you are stuck with the truck by the time they fully engage or is the truck just wearing in as time goes by? If the truck had behaved like it does now when I test drove it, I would never have purchased it. I would be overjoyed to have the truck drive the way it did when I first bought it.
I thought the Tech2 was phased out for new cars years ago, but I wasn't sure. The dealership says there are no codes present, so I assume they are using the correct software (may be a big assumption on my part). Can you please tell me more about the TSB flush? If you have a TSB number or title, I will look it up and try to get them to do it the next time I get the oil changed.
I'm not sure it is misfiring--it's just a clunky shift between V8 and V4 mode. The temperature has a lot to do with the behavior--it was in the 80s last week and the V8 to V4 transition was almost seamless (one minor jerk/clunk on the way home). When it is colder, it jerks, clunks, or shudders on the V8 to V4 transition probably half of the time. I mention this to the dealer every 5K miles when it goes in for an oil change--they try to pull the codes and see nothing. The V4 to V8 transition is smooth. Infrequently, when going V8 to V4, there is a kind of resonant metallic sounding vibration, as if a motor mount were failing. There is never any problem when going V4 to V8 other than the PEV squeak that I have been unable to remedy. Thanks for the replies--I'm just trying to determine if there is something else wrong with my particular truck while I still have the extended warranty. One fellow here at work with a 2015 model has some of my problems and a lady with a 2017 said she never experienced any of the issues. I'm not sure if they fixed the system over time or if my truck has issues.
Thanks for the advice. Regarding the vxdiag device, that's an awesome price for an MDI substitute! However, I have access to a Neo Fire at work that also performs the J2534 pass-thru for diagnostics (SPS/Tech2WIN). The truck is not showing any codes at this time and the dealer tells me that SPS has no way to force a re-learn. I haven't played around with the dealer tools, but I seem to recall reading elsewhere that there is not a way to clear learned behavior. I was hoping someone on here could tell me if that is true or not. Regarding the camshaft/lifter issue, how does one know if a collapsible lifter is failing? Are there any other signs beyond the periodic stumbling I am seeing? The AFM works flawlessly at times and jerks badly at others--it all depends upon the speed, temperature, and engine load. Since I have plenty of warranty left, I have no problem taking it to another dealer, but I want to make sure I understand the symptoms properly so they don't blow me off, too. The slamming is definitely worse in the winter (as I said, below about 45 degrees), which is when I drive the truck the most. I have old cars that I drive during good weather. When I get back into the truck after driving the old cars, it makes me want to move somewhere warm where I could drive the old cars all the time. Thanks again for the replies!
This may be a rather strange question, but is it possible to reset the learned driving habits? My 2014 GMC Sierra 1500 SLE 4x4 crew cab drove great for the the first year (new to about 10,000 miles). The truck was very responsive and the AFM was not bad then--it only kicked in at about 45 mph or greater and it was not objectionable. After about a year, the AFM started engaging much more aggressively and at lower speeds--the truck would periodically jerk violently when it entered V4 mode. It began trying hard to avoid downshifting, so there is absolutely no power when you turn corners or start up a hill unless you really shove down on the gas pedal. I distinctly remember a coworker saying, "What's wrong with this thing?!?" soon after the clunking and other stuff started. The dealer said it was learning my driving habits and everything was normal. Now, I have 57k miles on the truck and I really do not enjoy driving it anymore. I have about a 25 mile commute with long stretches of 35 mph speed zones. If I don't drive in M5 or activate the Range device, the truck repeatedly goes "CLUNK, lug, SQUEAK!" as the AFM engages, the truck lugs along for a bit, and goes back to V8 mode (with passive exhaust valve squeak, of course). I have noticed the clunking is much worse when the outside temperature is below about 45 degrees. The dealership says I am stuck with this behavior because it has adapted to my low-speed stretches and there is nothing I can do about it. They say most of their similar complaints come from people who drive at lower speeds. The truck has only been maintained at the dealership--I got tired of them saying I was not maintaining my last truck properly (Mobil-1 changes at 4-5k miles or 45% oil monitor remaining, coolant and transmission flushes at 30-35k, and all fluids replaced at 50k miles, mind you). I have had them do far more maintenance than recommended and I don't hesitate to throw this fact back in their face when they start to say I have done something wrong to cause the bad behavior (they said going too long between oil changes probably caused it until I told them to check their records). They tried pulling the battery and it didn't help anything. I would love to have my truck drive the way it did when it was new. I know I could get a tune, but I have an 84 month, 84K mile warranty and I don't want to risk having too many increments of the flash counter. My dealer says to get a tune when the warranty expires, but I doubt I will keep the truck that long--I honestly don't have much faith that the drive train will hold together. The constant "clunk-lug-squeak!" reminds me of the clown cars you see at a circus. Does anyone know of a way to reset the learned behavior or do I have to live with it until I get rid of the truck? I can get access to SPS if there is a way to resolve this via the dealership tools. Any help would certainly be appreciated!
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