anthonymason59223051

i know this is an older thread, but another thing that it very well could be is the vacuum pump. one way to isolate it is pop the belt off and start the truck. some noise made by it is normal.

finally got the time to do the low-side fuel pump yesterday... was starting to get to the point i was having extended crank times on start-up, a felt miss-fire at idle (not a dead hole miss but noticeable) and mild surging at cruising speeds when you increased load (like press/hold the accel button on cruise.) went for a drive before with the scanner to see where i was at on pressures and it was showing even lower erratic readings than before. before it was 24-64 min-max, now it was down to low teens to 51psi and had to feather the throttle for any kind of moderate acceleration. after replacing the pump, it is now reading upper 30s to low 70s and acceleration back to normal, no more coughing or stumbling, smoother idle, faster start up than it has ever been since i have owned the truck starting in February of 2021. it may not be your problem, but it is certainly something to look into!

on 5/02/25 i got the p2635 code and i am having some of the same symptoms as you are describing and have been for a while (maybe 3 or 4 months)... under moderate accel from a stop it will hiccup or cough, the only way i can describe it is it sounds like the truck is making the sound "puh". then it immediately acts like traction control engages and it falls on its face. looking at commanded versus actual high side pressures with no load in park is see a commanded of 881.8psi and actual of around 750-770psi. low side pressures, my scanner does not show commanded low-side but i can see actual pressures bouncing from 40-60 give or take a couple psi, verified with a mechanical gauge. while driving, the high-side stays CLOSE to commanded but always under by 50-100psi. but low-side? the graphing feature has the low-side looking like a seismograph during an earthquake, 24-64 min-max. i do NOT have the gravel sound you are describing though. it only threw the p2635 one time on 5/02 and has not come back after clearing, but the fuel pressures remain all over the place. my truck is a 2018 Silverado CCSB 4x4 LT TexasEdition with 109k. i figure it is probably about time for a low-pressure pump anyways... they are cheap enough through RockAuto. i will let you know how it acts after. when i pull the heads for a cam/lifter swap, i plan on doing the HPFP since i will be right there. going to throw an L86 intake and throttle body while there as well since it will need tuned anyways HAHA!

i had gone with the mevotech ttx lower joints when i rebuilt the front end on my 2018 LT texas edition ccsb 4x4 (roughly 90-95k miles) 13 months in and one of the grease zerks wont take grease, the other took grease but broke off trying to get the hose off. both of the boots were split after 3 months... discovered that fact when they started making noise. still have no play, just noisy. my opinion is the joints are good, but the boots are junk. now that i cant grease either one i am either going to "downgrade" to the supreme to get the better boot or go OE when they start to get excessive movement.

i have a 2018 Silverado LT TexasEdition 4x4 with the 5.3... 104k on the clock. has had 2 rounds of lifter failure. once at 27k and another at just under 78k. only thing keeping me from being outa pocket second round was an extended warranty. i know nine (including myself) people who have owned one of these trucks with either the 5.3 or the 6.2. seven have had lifter failure at one point or another. myself and one other have had it happen twice. i may be dealing with a small sample pool in the grand scheme of things, but it lends itself to more than just infinitesimally small probability. not arguing, just offering the data i know to be fact.

i have a 2018 Silverado LT TexasEdition 4x4 with the 5.3 that i purchased preowned. it had 2 sets of lifters and a camshaft by the time it hit 78k. powertrain warranty and extended warranty kept me out of losing money. i am looking to upgrade to a 2024 or 2025 Sierra Elevation 4x4 with the LZO now that all warranties are lapsed at 104k. anything you might suggest?

they had one a couple months ago on a saturday that i was eyeballing on the lot with 11 miles on it, everything i was looking for but had the 5.3 instead of the 3.0 duramax. leather buckets, thunderstorm grey 4x4 GMC Elevation for under 54k. the next monday, we went back, decided to get it even though it wasnt the engine i wanted. sticker price went to just shy of 64k. salesman informed us of the incentive program that just passed. didnt want to tell us the previous saturday bc his cut was going to be much smaller if we had gotten it. screw that guy lol

i have some equity depending on what is offered as trade-in value. pay-off is a little under 14k. i tried to be smart and pay extra when we could afford to do so. our credit union the more you pay, the lower your minimum payments are, but we continue paying what the initial payment was when we got it. KBB shows 18-21k trade-in and NADA shows 20-23k. im not the type to "dont lowball, i know what i have" but i actually know what i have and what it is worth, if a dealer offers around or even a little lower than that i might do it. i have good credit, and i just missed out on a killer deal a little bit ago with the incentives the 10k off MSRP that GM was offering. i just was not in a position to pull that trigger yet. when the incentives roll back in or another deal comes up, i might just jump at the opportunity.

there are more reasons for thinking about it sure! at least for the options i am looking for. reason i have to have the buckets with console is i have a baby on the way. rear vents are a necessity and the 40/20/40 split bench doesnt offer them. leather for ease of cleaning. i love my truck and so does my wife. our truck now is our primary vehicle when it comes to trips more than going to the grocery store. her back injury makes it very uncomfortable for extended periods in her 2018 malibu. we live in OKC and my family resides in Tulsa. her family lives closer to Joplin.

my main concern is with the reliability of the 6L80 and the AFM lifters. my truck has had 2 sets of lifters and the trans is fine for now, i would hate to have either happen and have a repair bill in the thousands and still pay a monthly note...

the 2018 Summit White Silverado is a 5.3/6L80 4x4 with 104k on the odometer. purchased at 77,500 in february 2021 with a 3yr/30k extended warranty, 2" RC leveling struts and front end completely rebuilt during install (RC upper control arms for correcting joint angle up to 3.5 lift, ACDelco lower ball joints, inner and outer tie rods, moog sway bar links and bar bushings). S&B closed box CAI, custom axle-dump magnaflow exhaust with flapper valve delete, custom tune using HPTuners (done around 90k) to disable AFM, remapped shift points and TC lock-up (no lock up until 5 and 6th gear). pill flip on trans thermostat. grill shutter delete. 1.5" spacers on stock 17' 5spoke wheels with Bridgestone Dueler AT Revo3's in LT265/70R17. service history showed a AFM lifter failure at 22k. all necessary parts replaced long before i purchased. less than a week of ownership, another lifter failure needing camshaft, all afm lifters, oil manifold, and gaskets. 2 rounds of lifter failure before 80k. the spec of Sierra i am eyeballing is a 2024 Elevation 4x4 in either ThunderStorm Gray or Sterling Silver Metallic with the 3.0L baby duramax and a 10spd, bucket seats with leather. any other options dont really matter to me. the leather buckets already bring all i would add. the reasons we are highly considering upgrading are: 1. wife has a minor back injury and heated seats would be a lifesaver for her 2. leather is easier to clean than cloth for minor spills and day-to-day dirt. (correct me if i am mistaken) 3. 6L80e i dont have a lot of faith in. 4. the silverado gets 18mpg on the highway where my buddy's 2024 silverado with the duramax gets 24 in the city while pulling a boat. 5. i still owe on the silverado for another 3 years knowing another round of lifter failure can happen any day, and tc can go tomorrow, no warranty. would be cheaper to buy a beater than to repair 6. a new truck would come with warranty, roadside assistance, and a loaner while in shop if ever needed. 7. i want a new, nicer optioned vehicle and imho the sierras looks WAY better than the silverados even though they are basically the same truck i guess this post is to have you guys weigh in with your opinions, what to look out for, if it is even worth looking into more than a hopeless pipedream, should i keep what i have or any other suggestions?

i am a little late to this party but mine is doing the same thing. have added maybe 16oz over the course of the 2 and a half years i have owned my 2018 lt texas edition silverado. occasional coolant smell but usually only at traffic lights, figuring it was another vehicle around me. came home and smelled it in my driveway. have been keeping an eye o coolant level and really havent had a noticeable drop in level. fast forward to today when i was under it inspecting suspension. going to be putting leveling struts and upper control arms on it, figuring im already there, replace all that needs done... look up and see a drop of coolant that hasnt fallen yet on a brace. radiator support is damp, radiator tank is damp, looking through the cooling fan and the and the bottom 6 or 7 tubes of the rad core is damp. cant really tell if it is a cracked tank, split seam where the core attaches to the tank, or the core itself. will not know until i get the time to replace it.

update to the issues i had on mine, the headlight housing had a cracked housing on the top going from the adjuster around the front and back around the upper mount along with a hole just over the HID ballast, with standing water in the bottom of the headlight. i pulled the headlight out, drained it, scuffed and epoxied the crack back into place with some JB plastic weld. got the pieces to puzzle-piece the hole and epoxied it as well. drilled a couple drain holes in case the epoxy doesnt hold. a $25 repair for now until i can get the funds for a new set of OE housings at a price of $1,200 up to $1,600 (each). the p0700 my truck threw was for the DRL. i would highly suggest taking the assembly out and inspect for cracks or moisture.

that thread has a pdf in a reply about a TSB for the p10e4 and p2535 that sets due to water intrusion into headlight housings and/or the connectors to them. i also just had the p10e4, p2535, and p0700 set yesterday. the 2 codes listed will not trip the MIL but will will store the code. the p0700 seems to be a separate issue that i have yet to diagnose on my truck being a generic code that basically says "something is wrong" after doing some quick research, it looks like all of the codes you are experiencing besides the p0700 all have me thinking to have you look into your headlightsand/ or connectors for a start