Chuck FB

When a new tire comes out and if it gets the right "traction", that is slang for over hyped marketing !, that can really sway the buying customer and most tire shops will probably be only too happy to sell whatever that is rather than caution a person on it as its too new a tire to have shown itself for what it can do or have had a chance to fall on its face yet and so buyers get on the new tire flavor of the month. This hybrid tire theme of an between a all terrain and a mud tire does make sense I suspect for those that are looking for a tire that has better mud performance than an all terrain but better on road manors and in theory longer lasting than an all out mud tire. Obviously like anything there will be those tires that may hit the mark on that target better than others. The Goodyear Duratrac was one of those such tires I would say that was edging into that segment as a so called aggressive all terrain, some raved about it and was their go to tire but some not so much due to tire issues and there was a reason why Goodyear phased them out for a slightly different version called the Duratrac RT that has closer spaced lugs. My brother had a set of the original Duratracs on a Jeep TJ and right off the bat he was not happy with the tire noise but it just got worse and worse and it sure never helped matters that he had waited too long to rotate them and by then they were beyond help, a wavy deep/shallow tread all the way around each tire which I gather could be a theme with that tire. Ended up taking them off way before they should have been worn out and threw them in a corner and instead went with a set of Toyo AT3 and so far they have worn perfectly and way quieter. But again who knows these things unless someone speaks the truth about weird quirks about a tire. My set of KO tires, early on I had gone on some off road trails in Colorado and while I was fairly slow and not doing anything aggressive, it took very little time before I started noticing chunks of rubber missing due to the sharp rock some of those trails have. It was then I started learning that the KO tires were not all that when it came to gravel as the tread was known to chip bad, however most of the miles those tires had on them at the end were a high percentage of highway and they lasted well although they did have weird shoulder lug wear but won't claim the truck wasn't partly at fault, they were a bit on the noisy side. The tire shop I had bought them from was shocked that I ended up getting that many miles out of them and I could have gone a bit more had I wanted to push them past where I like to put new tires on, I had 55000 miles on those tires. Where I live there are a LOT of gravel grid roads and roads that go for long distances that the oil patch and forestry use a lot for access and of course farmers like myself living in a rural area and travel gravel grid roads to reach the fields. So its a great testing grounds for tires to see what punishment they can take if put on trucks that are ripping up and down gravel roads out to oil leases and so on and the original KO tires were a total flop in that type of use for a variety of reasons, tread chipping off like it had gone through a meat grinder was the visual one. The KO2 comes out and that turned out to be a flop as well in that type of use, stone drilling like crazy and the carcass failing way before the tire was worn down is what I was being told by tire shops. I haven't had any discussions with tire shops over the KO3 so I have no insight there but having said this about the past A/T BFG, the tires that shops around here that are honest about it have a very short list of tires that can take that sort of beating and don't have the tire fail. By the way the KM tire line and I've had the KM, KM2 and KM3, they can't handle the gravel either as they chip and they end up blowing up the carcass with major tire failures. Loose crushed gravel is one horrid environment for a tire to come out the other side of relatively unscathed. By the way BFG does have a 60 day satisfaction guarantee they claim on the HD Terrain and so they claim the buyer can return the tires and swap out for a different BFG tire I assume, has your 60 days long past by now ?

Yes, and also I had the thought as you mention different climates and lets say it doesn't rain that often but the highway in question gets a buildup of fine tire rubber and oil and coolant leaks creating a situation where when it does rain it can turn the surface into an oil slick until the rain and vehicle activity on the surface wash the contaminants away. Or its a different or lack of road slope that holds water or the surface is smoother from being recently paved without having rolled in the small pebbles to help with rainy road traction, and blame the tires one currently is running on rather than the possible change in the road surface. So many variables and muddies the water if its the tire or the surface variable. What makes me roll my eyes at tire reviews on tire selling sites is so many reviews have lets say 1000 miles on their tires of whatever brand they just went with and give their tire a five star rating simply because they chose that particular tire, rather than the reviewer who has gone through the useful life of one or more sets of the same tire and has something to base their review on.

I only ran one set of the original KO tires long ago and never had any issues with them either in that regard but then again I don't force the situation the odd time when I did encounter heavier rain and never do with any tires as its asking for trouble, certainly when a tire is on the worn side the risks go up. So who knows if there is more to that story about the KO2, its a popular tire that guys were putting on as oversized and wider tires on light vehicles, that's like a light kid skiing on adult sized water skis as it doesn't take much speed to keep the kid up on the lakes surface. At some point physics take over with tires, like driving too fast on slick ice roads and ending up on ones lid or worse !. Never the less BFG themselves pointed out one of the redesign features of the KO3 with that longer angled groove across the tread pattern as that was meant to help evacuate water for a reduced chance of hydroplaning is their claim. I was in Costco today and I knew they handled the Bridgestone Ascent so I took a look to see if they had any and while they did, it was the non LT version so the tread is not quite as deep. I spoke a bit to the manager and she said they look the same, one version vs the other in the same size tire. Physically seeing them answered my question as per the spacing of the shoulder blocks, I prefer a tire that has more shoulder block spacing for traction but that can have its negatives with weird shoulder wear over a small groove spacing like this Ascent has. I am not a fan of tires that have a solid shoulder, longer lasting yet most likely but not meant for dirt traction. There is no one tire that can do everything the best.

As I believe I asked before, what the timeline was relative to the last time the engine oil was changed or any other maintenance that could have caused a foreign object to be introduced into the engine by way of the oil or the intake, including someone tampering with your truck. Also am wondering if by chance for example a small roller bearing came out of a roller lifter or one of the rockers and started a chain reaction of metal being able to get past the filter ( cold engine start filter bypassing for example ) and went through the crank bearings. I imagine it can be hard to tell after a bearing gets chewed up and sends metal around through the engine, the oil pump would have damage at that point so destroying any prior evidence. But it certainly could be a slight manufacturing mistake on the crank, the connecting rod or the rod bearing itself that eventually lead to it being spun in the con rod. I assume dealers don't spend too much time trying to sort out what could be hard to prove and if warranty covers the situation, a new engine and oil cooler system gets swapped in and life goes on. Like others I am curious what the oil change schedule was typically like and if there were a lot of idle hours on the engine or a lot of very short runs ( potential fuel dilution ) etc at times. I could be wrong in my thought but I rather doubt a complete/new engine replacement swap being done would affect future resale as long as the new engine is running well and perhaps some oil samples taken after its broken in to prove to you or a future buyer that its not showing any abnormal wear. The issue more so I think is when a particular vehicle platform gets a bad reputation rap like the 6.2 GM or way back with the GM gas block 5.7 diesel as buyers run the other way based purely on reputation and resale plummets as a result.

There must be something quite different about the rubber compound then if at slow speed you can notice quite a difference in wet traction from the Goodyear to the Bridgestone. I've read in the last few years about the comparison between the ATW3 ( I do own a set on another pickup but have not had enough varying conditions to make claims other than they seem fine driving down the highway so far ) and the BFG KO2 comparison, that the KO2 was not good in the wet for traction and has hydroplaning issues due to its tread block design that did not evacuate water well. That does surprise me that the ATW3 was not working out so well as for what its worth I certainly saw a lot of positive comments about that tire and my multi brand tire dealer highly suggested the Falken for my use due to some gravel use over the KO2 for sure but also the Toyo AT3. What did you do with the factory Goodyear tires, hang onto them or let them go cheap at the tire dealer.

So what prompted you to purchase tires right away vs getting some of the life out of the factory tires. In asking that, I am not really a fan of Goodyear tires and also not sure if the tire failures I have seen shown online of the HD factory 20" Goodyears is a batch thing or more wide spread but makes a person wonder. The tread is shallow for an LT tire and certainly no mud inspired tire but seems quiet on the highway. I ran dedicated winter tires this last winter on a different set of wheels so just kept these factory ones on for now for spring through fall use. On my list of possible replacement tire models when I do need new tires as an all terrain makes the most sense to me for my use, the Falken ATW4 is on that list as well as the Toyo AT3 or anything else that may strike my fancy between now and when I need tires although I wouldn't be planning on running them during the winter either. I'll be curious to hear what you think of these Bridgestones as time goes on as they are certainly a lighter tire than the Falkens ( and that can be good for fuel mileage and ride etc but also bad if its not tough enough ).

I can't claim that what you have seen said is entirely wrong as more engine platforms have gone over to lower tension rings and that has caused increased oil use as a result of that idea of reducing friction but the side effect of more oil slipping by the rings. However even on this forum there are those that have done a fair bit of towing with their trucks and not experienced high oil use along with some that have had higher than what has been considered normal oil consumption. Why the differences is a good question and I realize that the internet can drag out more of the bad then the good due to those that are not having an issue don't have reason to talk about something that is not a problem vs those that have a problem and are openly spreading around their frustration over an issue. All I can say so far with certainty from my short term experience with my own truck given that I have relatively few miles on it and have not been towing with it so far, is that its not been showing up to be an oil user under my low load use conditions. I was changing the oil very frequently for the first few oil changes because of wanting to do the best I could do flush out break in wear metals. The last oil I dumped out was from use this winter and was a 0W-30 and being used in our not so lovely Alberta winter temps and no doubt higher risk of more fuel dilution although by this spring with more moderate temps and my usual 100 mile plus round trips to town all along I can only speculate that most of any gas that may have found its way into the crank case would have gone through the pcv system. I estimated that perhaps the oil level had dropped around 1/16 of an inch in that 2500 miles and this was being parked in the exact spot each time I check the oil. A few weeks ago I had a brief conversation with a mechanic that has run his own one man shop for years and have had him do work over the years on a prior pickup and he works on various brands of pickups and so forth ( leaves the diesel end of things to others that have the specialized equipment for that ) and his brief comment to me about the 6.6 gas is that its been doing good overall BUT with the caveat that as long as one changes the oil often. Unfortunately he never had the time to elaborate beyond that as per what happens if its neglected but I know over the years he has worked on a lot of Ford half ton pickup engines replacing the timing chain and phasers and so on and that goes back to the 5.3 and the 5.0, 3.5 etc and the biggest determining factor often was how often the oil was changed or not as so many vehicles out there are going by factory minimum service intervals and its causing a lot of premature wear on some components.

I think if I am understanding the chain of events properly, you never happened to personally check the oil level right after the second free oil change done at 5700 total truck miles and indeed the big question would be if they totally goofed and shorted you by two quarts if not even over that amount. You will probably have some answers in 1 thousand miles one way or the other, I certainly hope for your sake and the sanity of us L8T owners that the oil change boy never even checked the level after the oil was added. Sad but true, it seems its to ones benefit to double check worked on items if its possible to do shortly after its been performed and as others have stated this engine is sensitive to consistency with its shown oil level depending on slight variable slopes one may park on. I try to park in the same location each time ( I often park in the garage so that's easy ) to check the level after its sat for a good while or overnight. So if anything suddenly shows up as off I would know about it shortly.

Have you been doing your own oil changes and if so any particular oil filter brand you have been using. Also within that theme of oil changes was the oil changed just prior to this occurrence or a while back. I am purely speculating that something mechanical either let go due to a defect and a chain reaction such as a valve dropped after a valve spring broke etc or I suppose there is a possibility that a cam or crank bearing could have turned restricting oil flow and the oil pressure would remain good on the gauge but in reality starving parts of the engine from adequate oil. I guess that remains to be seen if the dealership does a tear down or if they find a mess and determine a new engine gets dropped in and the original engine gets whisked away without a proper look.

Were you noticing some oil consumption even early on or was there a sudden change and that it started to use oil. Also what oil change mile intervals has been done so far and what oil brand/type has been in the engine when its been using oil.

I hear you on the valid reasons these days to shy away from the diesel platform unless one is expecting to do a fair bit of heavy towing as well as on a lot of grades due to the engine braking that the big three diesels are equipped with. Shorter runs and more so in a cold season climate and with all the emissions garbage they have strapped on the diesels, its not really the best choice and then the fuel price difference takes away the fuel mileage benefit. I farm or should say until recently and surrounded by diesel equipment and highway tractors etc all my life but seeing some of the downfalls of the diesel pickups I decided it was not worth the extra hassle since my use case for the truck I even bought is up in the air as per an HD truck and burning more fuel over a half ton gas. Being that I live in northern Alberta and we certainly get winter, I can say that this L8T and it has the rad shutters on it as well, I am very pleased with how quickly the engine warms up with minimal initial idle time before I ease down the gravel road with light engine load for the mile and a half to the highway and the engine is almost up to full temp even in extreme cold conditions, vastly different than how a cold blooded diesel reacts. I was laughing at the vision of the single axle trailer, I don't know if yours is like a typical open deck snowmobile trailer which would be on the same order as towing back in the day of those small tent trailers, they are not enjoyable to back and certainly not with a long wheel base truck over a short suv. I'd say one of the items I wished a gas engine had was an engine braking system when it comes to towing as over the years with older gas or non jake brake equipped diesel tandem trucks and descending grades and not even all the long of grades certainly compared to the passes in Colorado or similar, having to gear right down and I do mean right down so the truck is just crawling so the engine has the mechanical advantage to control the speed, that is painful and so when we bought highway tractors with jake brakes for pulling grain trailers, that sure was a game changer and even for flat ground slowing down for an intersection and not having to use the foundation brakes.

Even living at 5400 feet, already that takes away a good chunk of power your truck would otherwise have cruising along in "the valley" if that is where you typically drove in your former state. I wasn't sure how long ago you bought your 2500HD so if I was you I wouldn't be towing with it at all until it has some miles under it and at least its first very short oil change period dumping out the factory oil ( its always unsettling to cut open the factory filter even after 500 to 1000 mile from new engine wise and see the sparkles and easily seen bits of mystery metal/aluminum shavings ), and that applies to the transmission and rear end gears mating in before subjected to high loads. I was through Silverthorne a couple of times but on highway 9 after exploring Rocky Mountain NP ( elevation 12000 ) so crossing over I 70 and never did go further east of that point on I 70 to experience the tunnel or having taken Loveland Pass which oh yes I hear its interesting all right due to how winding it is rather than a high speed freeway and have always wished I had taken the time or had the time to have done Loveland. Your Colorado was doing remarkably well to my way of thinking towing that fast on those grades at that elevation as the top of Loveland is at 12000 feet !. In that general area to the south I have done the passes on highways 9, 91 and 24 and the highest pass of those three is Hoosier at 11550, and also been over ones like Monarch pass and Red Mountain pass etc. The highest I've been on a pass is Imogene at 13115 and then ones like Pikes Peak and Mt Antero at 14000 feet and lets just say the old water sprinkler technology GM throttle body was not happy at 14000, can't imagine how awful it would be to be up there with a sea level carbed engine !. Certainly if one was doing a lot of towing over the passes in Colorado the diesel or a turbo gas would be tempting for what they can do at elevation but have also heard at least with the F150 3.5 as an example, push them too hard for too long towing up those grades and a chance it may "ecoboom" and that wouldn't make a person feel very good in the pocket book once off warranty.

What elevation roughly do you live and drive at in your part of Colorado. Also have you had a chance to pull that car hauler loaded over some of those same significant passes yet and wondering which exact passes those are and if I had been over any of them myself by chance years ago when doing a bit of traveling around Colorado exploring ( not pulling anything thankfully as it was enough for just the truck loaded to the max with camping gear .. 4L60E tranny explains it all ! ).

That indeed gave me the idea to try an address in town, yes its a city but no one calls it that here but I digress. Now if that dollar figure is actually correct is hard to say but it gave three options as per two different shipping companies and one of them a shorter time frame vs a slightly longer time frame. Honestly I don't know how any of the times make sense in days as they claim 6 days delivery, it used to be more like 6 weeks to maybe eventually get something. So I chose that same or similar rotor to give it the same weight theme as my last item I did in my other comment, so around that 140.00 Canadian funds for the one rotor and then will just list the shipping fee quotes on their own in order of price and time line. If that is factual, that is some vast spread of prices even with shipping and time line. There was only one quoted price on the Canada Post shipping and no delivery date was generated either. I keep wondering if there is something they are not adding because of the tariffs, surprise fees for that not being calculated as some changes with the US fees to Canada just changed the week following Easter although that may be more so shipping product TO the states rather than to Canada but its devastating some major companies in Canada and will wipe out a major portion of industry and jobs if that isn't walked back. Warranty is always an issue when shipping items vs walking into a store front, even something ordered from within Canada could be a nightmare to warranty and these distribution sales companies know that and have full control over denying warranty. April 29, Fedex, 62.89 CAD April 28, DHL, 129.86 CAD April 27, Fedex, 308.95

Yes, if I could pick a shipper depot like I was able to do with Amsoil and also in so doing skip the Canada Post theme, that would be interesting to see how the shipping costs would change.

That about sums it up, I am in a rural farming area and actually various store type companies that have an online presence as well such as Home Depot Canada as one example of various ones, they could not physically figure out how to ship anything to me which is totally retarded but there it was. Some of these shipping companies have no customer walk in depot as its all drop shipped and since there are zero companies that ship to my door step, they can't ship to me but also some stores don't have a system where it can get shipped to them so I am just SOL with companies that conduct business like that. A while back I got set up with Nick to be able to purchase Amsoil products as I figured out through the Edmonton Wearhouse since Amsoil happens to have that Alberta presence, they told me which shipping company they would ship to that I can walk into their depot and pick it up and last week I made my first order and was able to go to Loomis and pick it up. Amsoil must have a deal with the shipping company I would guess and if over a certain dollar value is purchased the shipping is free and even if the order is not up to that value its not some huge shipping fee, obviously its within Alberta for me and going to a location they commonly ship to. The funny thing is that Nick helped me sort all this out as I could see that the person who is or was locally as a dealer whom I spoke to once a few months ago was not on the same page at all as what Nick happens to be. Actually I didn't realize that Rock Auto had a 5% off discount code that is always available, interesting. But the key or at least with the shipping method they automatically calculated on for me, very light items is what could make some sense to order from RA.

So I went onto Rock Auto and by the way its the CAD prices I had it list out as so there are no dollar conversions happening within the shipping portion. I did a few scenarios and this would be shipped through Canada Post which I suspect would be higher but that it would get it close to my location. I don't think Rock Auto or as deep into it as I did will give a break down of what charges there are other than the total delivery price. First example is choosing all light items as a order of a few items together, set of spark plugs, engine air filter, trans oil filter, rear diff gasket, trans pan gasket. That added up to 228.29 in parts and the shipping was 156,94 for a total of 385.23 Second example, one set for an axle, GM brake pads that included the sensor for 174.41 and the shipping was 152.84 for a total 326.98 Example three, GM brake pads and again a set for one axle that did not include the sensor for 110.40 and shipping was 156.94 for a total 267.34 Example four and this is where the weight factor really shows up even more as its ONE GM front rotor for 139.06 and shipping was 379.40 for a total of 518.46 ... and again, ONE rotor. So that shows what happens when one ships any weight to my address and no it does not come to my front door as I have to go and pick it up. I would have to see if they even ship by any other shipping company and to a shipping depot in the area or if this is all they are set up for, for a comparison.

I am not sure now if duty is slapped on that or not as it depends on the product but there was a brokerage fee as I would have to make up a pretend order to see what type of fees it was adding but shipping was HUGE and even on some light items. Now there are tariff charges on some items as well but have not looked into that. Forget ordering heavy parts such as rotors or anything of any amount of weight as the shipping became beyond already insane. Like when I ordered the paper manual from the printing company Helm, the manual was 50.00 USD, and yet by the time it was shipped up here it was if I am not mistaken just under 250.00 CAD. Having a company shipping large quantities of an item through their regular shipping channels is one thing as its being shipped in a bulk way, but shipping an item on its own is where they really get a person.

For the fun of it sometime I should go through the motions of pretending I am going to order them through Rock Auto as I know some time back I did a prospective order on something through them and by the time duty and shipping and dollar exchange was included, the price was 2 1/2 times as much as the initial price that someone in the states would be viewing. Which goes back to the price of the same GM pads here in Canada relative to various aftermarket pads. Don't get me wrong as per the quality etc of the factory pads as I have nothing to complain with them so far but also have not towed with the truck yet. The other day I had swapped over from my winter tires to the factory tires and all the surfaces of the rotors looked perfect with no grooving other than some rust/staining shadowing due to the truck sitting for a while between uses and the salt causing slight rusting where the pads happened to be sitting. Pad life looks even from inside to outside pads so far but I only have 6000 miles on the truck. I haven't had any noise from my brakes so far and they act very smooth. I wonder if the 2025 model truck has a different compound compared to trucks built somewhat earlier that have experienced really short brake life or if its something entirely different at play with the system ( like automatic braking due to the cruise or stability system ) or a caliper issue that was causing the high pad wear.

That is a good question and from what I see for example on Rock Auto and not to claim they even offer the actual factory pad material but a lot of the GM pad offerings they have are listed under "daily driver" and some say ceramic. However even if a pad is listed as ceramic doesn't mean its the same blend of materials as a competitors ceramic pad. Also on Rock Auto they have the "Heavy duty truck and tow" section and more of the pad brands there are semi metallic and they list a ACDelco severe duty semi metallic pad as well. In reading up about pad material it seems to come down to the fact that ceramic pads are easier on the rotors but don't have as aggressive a braking performance and a caution when it comes to braking performance in cold weather if the brakes are cold before the pads have had a chance to warm up. When it comes to towing/heavy loads they always point to semi metallic or a hybrid type blended pads for best braking performance and less fade and faster pad cooling etc but at the expense of more rotor wear/grooving. Put another way that a so called lightly loaded daily driver pickup may be fine with the braking performance of ceramic pads and prolongs the life of the rotors but a towing rig has high demands and the more aggressive semi metallic pads is really what one should be using, the last thing one needs is marginal braking and brake fade in the mountains when towing. One thing is for sure here in Canada as per outlandish prices for GM pads, a set of genuine GM pads through a local supplier is 413.00, a set of powerstop evo ceramic Z17 series is 194.00 and the more aggressive powerstop Z36 series carbon fiber ceramic pad for truck and suv is 251.00 as some examples.

I don't believe you had mentioned which brand and pad model within the brand that you had gone with as that would have a bearing on the noise as well as the braking performance. I had a bad experience with 100% ceramic pads years ago on a vehicle that I doubt was ever designed to use such hard pads and I had some near collisions because of the lack of braking effect with the glass like hard ceramic vs a pad that was a mixed compound that offered a lot better bite onto the rotors.

I am curious what made you decide to eliminate the brake wear sensors, some pad kits come with the sensors and as long as the harness plug etc isn't damaged I assume it shouldn't be too much of a pain to swap the indicators over to the new ones on the left side of the vehicle. What brand and model/spec of brake pad did you go with and did you reuse your rotors or swap them out as well. Also did you have very uneven pad wear when comparing the inner to outer pads on a caliper which typically indicates the slide pins are not as free as they should be or the caliper pistons themselves are not retracting that slight amount after the brake pedal pressure is released. Did you take a peek at your park brake shoes, which would happen by default if the rear rotors were replaced. Odds are unless you travel up to the rust bucket states during the winter or drive on the Florida beaches and salt up the brakes, I imagine the park brakes are probably in decent shape.

To your point of Dexos oils and then those oils that are perhaps considered slightly above but are not Dexos certified. An example and I might be able to go back and find it but it was a half ton chev truck owner in a comments section of a oil related video that had his truck from new and it has the 5.3 engine. He as he saw it meticulously changed the oil himself every 5000 miles using Pennzoil Ultra Platinum and thought he was doing an excellent job of maintaining the oil quality he was using as well as the OCI. I don't recall the exact miles on his truck but it certainly was no where near 250000, I believe just over half of that in total. For some reason he decided to switch over to the Valvoline R&P 5W-30 and had ran it for 5 OCI and it was that fifth OCi that he had a photo of his filter after about 4300 miles. The filter media was a dark brown and could see fine brown deposits in the bottom of the pleat grooves and it certainly did not look like what one normally sees on a used oil filter. That R&P had been removing a massive amount of built up deposits on the inside of that engine, who's to know what the status had been of the oil control rings and the drain holes in the piston when he switched over to the R&P. I was shocked at seeing that as there has been a lot of positive talk about the Pennzoil Ultra Platinum and in that sense that its considered slightly above the Dexos spec. The gist is that whatever is in the Valvoline R&P is helping reverse deposits and would stand to reason that if an oil with those additives was used from the start the deposits would be far less. Time will tell with the Mobil oil they just came out with as its being marketed on a somewhat similar theme to the R&P, or put another way it would suggest that not all the commonly obtained oils and that includes Dexos certified oils on the shelf are created equally. One thing is for sure, all the oil companies sure push to create fantastic claims for their oils and where does the truth end and the bs line begin, case in point are the mileage protection distances on some major brands and being in Canada, an example is Castrol Edge Titanium in the gold bottle with a "32000 km protection"

What speed were you traveling at during this run and what approximate ambient temp was it. By any chance had you had the engine and transmission warmed up prior to this 100 mile round trip as I find with my truck it sure makes the difference if its already been warmed up and not just engine but also miles put on to have the transmission and diff warmed up. For example I am driving to town from where I farm and using the same drive summary and note the reading when I get to town. Then upon leaving town as the engine was shut down to reset the reading and drive home the fuel mileage creeps up more due to the driveline having already been warmed up.