Down shift clunk

Paul_’18 Silverado · May 20, 2020

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 · May 25, 2020

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..