Jump to content

Down shift clunk

Paul_’18 Silverado

Recommended Posts

Paul_’18 Silverado Enthusiast

Paul_’18 Silverado

Posted
Posted

2018 Silverado Ld crew 6.5’ box

hey guys, has anyone had any resolve to the sown shift clunk?

ive been round dealer twice, first was a tcm re learn, that didn’t do a thing, second was a tsb for lead spring insulators put in between the leaf pack and load spring, raises ass end another 1/4” which I absolutely hate and still have the clunking, it’s going back again this Friday for the clunk, I’m getting really fed up as this isn’t normal, regardless of what gm says, any slack or play in the driveline will cause long term damages to whatever weakest link in the driveline fails first and on from there. Is there an actual fix that someone has finally gotten or is this just another ghost issues that when warranty runs out will cost a small fortune to repair since the issues wasn’t “that bad” under warranty and nothing was or could be done about it?

any advice info I can collect when I go in and take the shop foreman for a road test? Or do I have something that just “is what it is” $60000 truck and last one I ever wanted to purchase among the last few new truck I’ve had in the past not gm never had any driveline issues like this one I purchased brand new.

any info will help steer me in the right direction to argue with gm the fact that”it is not normal”

slick_rik84 New Member

slick_rik84

Posted
Posted

How many miles do you have? You might need the dealer to perform trans flush.  My 2017 8spd had a ridiculously rough downshift when it was brand new with about 500 miles on it. No joke, felt like someone rear ended you. Dealer said “transmission needs to learn your driving habits and should smooth out at around 1500 miles”... of course I had the initial “you have got to be f**** kidding me” reply.. low and behold, right at 1500 miles the tranny did start to shift smoother. Fast forward to 48k miles and truck is downshifting rough again and feeling like driving on rumble strips between 25-40mph. Took it to dealer again and they flushed the trans and replaced the ATF to a “high performance”. Truck is shifting smoother than ever now. We’ll see how long it lasts..

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • Black02Silverado
      HighMileage oils or stay with Dexos 1 ?

      By Black02Silverado · Posted

      Doesn't hurt to try.  It's my understanding that you have to run it at least 4 or 5 oil changes for things to get clean.  Think about it, your engine didn't get dirty in just an oil change so over time it will slowly clean. It's the safest way to do it and not have seal issues.      I remember  a product that came out a long time ago, AutoRX, it was an additive you put in the oil and then drove for 3k miles. Some saw improvements and some didn't. It was suggested to use a non synthetic with it at the time. Same observation, use a couple oil changes and give it time to work. It also stated it worked best if you could drive on trips to keep the oil hot.  I'm sure if you ask AI it could tell you all about it.
    • Dkd71
      GM discontinuing interior parts on a 5YO vehicle??

      By Dkd71 · Posted

      The part # is 84520447, mine does not have the cooled seats but I'm willing to possibly change the cover and foam if needed.   I tried that site and a few others,  added to cart and then paid. About an hout later I received a refund stating it has been discontinued. 
    • Chuck FB
      Installed Bilstein 5100's on my 2024 2500HD - Worth it - VIDEO + GIVEAWAY Inside

      By Chuck FB · Posted

      Thought I would add to what Bruce answered, not only do the HD models use the torsion bar system, there are I believe 5 different torsion bar spring ratings that are all physically interchangeable with all the HD trucks going from a two wheel drive 2500 all the way up to the duramax or a gas engine truck with a snow plow prep package front end weight capacity that use the maximum sized torsion bar. It starts from a 4400 lb rated set in 400 lb increments up to 6000 lb. If one wants to fine tune the ride for a certain truck application they can swap out the torsion bars. 
    • Chuck FB
      OIL CONSUMPTION

      By Chuck FB · Posted

      First off pay close attention to what Newdude pasted as he is a GM tech !.    I have a couple of questions which might cross off some questions others on this forum would be wondering about as well. So when was the engine oil changed prior to this trip, was it almost brand new oil or did it already have a fair bit of use on it before you started the trip.   Did you check the oil level on flat ground and was it at the full mark just before leaving on this trip which I gather from google map is about 700 miles or so. Why I ask and this is not the first time in history that has happened, that either a dealer or some other shop changed the oil on the vehicle and the vehicle left the shop and the owner ( you ) assumed the engine oil was full but in reality the person who changed the oil simply did not put enough oil into the engine .. it happens !. Also that a shop put the wrong viscosity oil in and an engine was not happy with that thinner viscosity and oil got past the rings at a higher rate than the proper viscosity. Not to mention if there was any leaking out of a drain plug or the filter gasket etc. 
    • Chuck FB
      Correct way to service 2024 l8t allison trans?

      By Chuck FB · Posted

      You could, although in the end it really doesn't make much difference what comes out in exact terms since it comes down to putting enough back in so that there is enough volume so that something flows back out once the trans is up to temp for the check procedure. I presume your putting a pan on that has a drain plug but its probably the same pan mold/size as at least a while back no extra volume pan was made for the gas truck version due to the exhaust cross over pipe issue. All I can say as per volume I put back in and this was based on changing out the filter as some is trapped in it that does not come out until its removed because of the way its made inside and my truck had sat over night with the trans having been hot when shut down and dripping internally before I pulled the pan. I went off of what the trans shop suggested as a minimum volume he found worked which was 9 1/2 quarts and I had enough flow out of the stand pipe that I knew I was right on the money once it slowed to a dribble and never wasted hardly any oil but it would be totally fine to throw in a full 10 quarts too. I guess personally I wouldn't ruin a perfectly good pan by drilling a hole in it, not with the cost of replacement pans up here or the dorman one anyway with the drain was 500.00 when I priced one out a while back, totally stupid.    I might not have said before but this trans oil type really expands with heat and I think its been said on this forum and the trans shop said the same so I wanted to try and hit the lower temp of the range vs at the top or go shooting above it as that would allow more oil to flow out which wouldn't be ideal. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...