Jump to content

2018 Chevy Silverado 1500 8 speed transmission problem

Captainmc

By Captainmc
in Troubleshooting & Recalls

 Share

Recommended Posts

Captainmc Enthusiast

Captainmc

Posted
Posted (edited)

Bought a brand new Silverado 2018 1500 with 8 speed and having shifting issues at low speeds. Highway speeds runs perfectly, but low speeds I can only describe as:

Clunky.

Jerky.

Rough.

Hard occasional bump or shift.

Accelerating or lurching forward causing me to hit the brakes hard.

Havnt had any check engine light yet.

Has anyone heard of a fix for this? Or am I going to be another unhappy GM statistic?

Edited by Captainmc
JimCost2014 Senior Enthusiast

JimCost2014

Posted
Posted
3 minutes ago, Captainmc said:

Bought a brand new Silverado 1500 with 8 speed and having shifting issues at low speeds. Highway speeds runs perfectly, but low speeds I can only describe as:

Clunky.

Jerky.

Rough.

Hard occasional bump or shift.

Accelerting or lurching forward causing me to hit the brakes hard.

Havnt had any check engine light yet.

Has anyone heard of a fix for this? Or am I going to be another unhappy GM statistic?

Welcome to the site. There are quite a few threads on this topic. I would start with your dealer, maybe open a claim with GM to see what they can do for you. It is unfortunately a problem that some trucks seem to have. 

 

 

 

 

Captainmc Enthusiast

Captainmc

Posted
  • Author
Posted (edited)
17 minutes ago, JimCost2014 said:

Welcome to the site. There are quite a few threads on this topic. I would start with your dealer, maybe open a claim with GM to see what they can do for you. It is unfortunately a problem that some trucks seem to have. 

 

 

 

 

Thanks. I know all too well about the whole dealership fiasco. With all the issues I had with my 2005 suburban and 2005 Silverado you would think I would have learned by now but here I am. I do still have my 2005 Silverado 2500 HD. Other than the pump rub and gauge cluster repairs, it’s an amazing running vehicle (160,000 miles). I’m thinking of keeping it in case this new Silverado leaves me stranded. Pretty pathetic to feel better about driving your old truck.?Interesting enough is that I have a 2015 Yukon and it’s been awesome so far. Shifts perfect with no issues yet. Does do the lugging deal in V4 mode but we are used to it now.  Just thought I would see if anyone actually found a real fix or had any advice  before I take the Silverado in?

Edited by Captainmc
1SLOW1500 Senior Enthusiast

1SLOW1500

Posted
Posted

This has been addressed but I would look at the service record. I understand it's new but that doesnt mean there isn't a service bulletin on it. 

I say all the time the 8speeds have issues. I was told not to buy one by GM. Anyways again it's new so may not be what you want but can be fixed with tune.

Captainmc Enthusiast

Captainmc

Posted
  • Author
Posted (edited)
4 hours ago, 1SLOW1500 said:

This has been addressed but I would look at the service record. I understand it's new but that doesnt mean there isn't a service bulletin on it. 

I say all the time the 8speeds have issues. I was told not to buy one by GM. Anyways again it's new so may not be what you want but can be fixed with tune.

I sure hope so. Love everything else about the truck except the terrible shifting. I heard that tuning it can void the warranty?

 

Anyways, just made an appointment to have the software updated so hopefully it

can help like I’ve heard it has from some other guys.  I’ll repost what happens 

Edited by Captainmc
  • 2 months later...
  • 1 year later...
Mstangr New Member

Mstangr

Posted
Posted

Bueller? Anything more? I have been experiencing the same issues with 2018 8 speed. 

 

  • 9 months later...
Randy Daggett New Member

Randy Daggett

Posted
Posted

I have been rebuilding transmissions for over 30 years and I just bought at the time a new 2020 Chevy Silverado 5.3L and I love it except for all of the little features that I really didn’t want but anyway let’s get to the 8 speed Chevy transmission, I have found that most of the time when the transmission is clunking or shifting hard at lower speeds is due to a faulty Valve body and THECM unit, or internal clutch packs that are leaking or just burnt clutches can cause clunking at low speed, the valve body is one of the most common reasons for clunking at low speed, but there can be burnt clutches or a defective one way clutch assembly, pump assembly not producing the correct pressures.

When ever I rebuild a newer 6,8,10 speed automatic transmission I always get a remanufactured Sonnax valve body, they are all dyno tested for internal leaks that cause clunking and many other issues!

 

 

dgstarr63 Enthusiast

dgstarr63

Posted
Posted

I have a 2021 Silverado 1500 4wd, 5.3, 8 speed. Every 500 or so miles it would clunk on a downshift to low when slowing up to a stop for about 1 to3 days and then quit for another 500 miles and start over. At 5000 miles my dealer installed a new valve body. It has been about 500 miles since the repair and is shifting perfectly. I hope this repair will be permanent.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Zane
      2027 GMC Sierra: Official Discussion

      By Zane · Posted

      Not sure about DFM tech but i know there's a stop/start deactivation button. 
    • KARNUT
      2027 GMC Sierra: Official Discussion

      By KARNUT · Posted

      I could be interested if they axed cylinder deactivation and at least have a button for stop start. I’m sure the HP numbers will be higher. I would want a longer warranty to help build confidence. I’m a less is more guy as I get older. A V-8 work truck model would be my choice. I know a few outfitters for custom additions I prefer. 
    • Zane
      2027 GMC Sierra: Official Discussion

      By Zane · Posted

      It's official. GMC pulled the covers off the next-gen 2027 Sierra 1500, and we got the first official look. Full breakdown here: https://www.gm-trucks.com/next-gen-2027-gmc-sierra-1500-v8-trim-changes/   The quick hits: SLE and SLT are dead. The new core retail trim is just called "Elevation". Two new V8s, a 5.7L and a 6.6L built with high-performance Corvette architecture roots. No horsepower or torque numbers yet. The 2.7 TurboMax finally ditches the old gearbox and gets the 10-speed automatic. AT4X moves to larger standard 35-inch tires with front and rear e-lockers, Multimatic DSSV dampers, and heavy-duty Jounce Control Dampers. Over 60 inches of combined display on Denali Ultimate and AT4X, complete with a motorized articulating center screen and an adaptive passenger screen. Seven simplified trims across the entire model line to clean up ordering confusion.   So let's get into it: New 5.7L and 6.6L gas V8s with custom active exhaust tuning and a Corvette connection. Is this the exact engine lineup half-ton traditionalists have been begging for? Purging the iconic SLE and SLT names after all these years to lean entirely on Elevation as the high-volume core. Bold move, or a mistake? That motorized articulating 16.3-inch screen that slides up to reveal a hidden dashboard vault. Awesome mechanical theater, or does it make you nervous about long-term durability? Physically lowering the headlamps in the front fascia to improve road courtesy and stop blinding oncoming traffic. Smart real-world engineering, or does it hurt the truck's aggressive stance? What trim are you putting your name down for on day one? Drop your first impressions below.  
    • Donstar
      Navigating senior years.

      By Donstar · Posted

      My overnight hospital stay turned into five.  I developed a post operative fever and an erratic  heart rate.  A blood clot in the lungs was the culprit.  This is apparently a common post surgical complication and easily remedied.   I was the youngest in a four bed ward and a Doctor with a Geriatric specialization was in charge of my care.  All of the nurses were good and some were outstanding at dealing with old people.  It was very evident that my age triggered a different level of care!  My advice to any senior going for a hospital stay is to have a trusted family member advocate visible.  If not, you will still be well cared for, but you may discover that your voice  isn't as strong as it once was! 
    • diyer2
      Gas Prices

      By diyer2 · Posted

      $4.25 85 oct. in town, down 50 cents.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...