Jump to content

Recommended Posts

Posted (edited)

So I have a 2017 Sierra 1500 6.2 8spd. 

 

When I start it up in the morning, drive out of my drive way and come to a stop sign, no matter how softly and gently I apply the breaks it feels like someone rear ended me just as I come to a full stop.  A firm clunk from behind.  It only happens for the first 2 or 3 stops (or 2 or 3 minutes if I don't come to any) and only when the truck is cold.  If I park for an hr or so and drive again it doesn't happen but every morning.
 

Any ideas of what it could be?  Been doing it for a while now.  Thank!

Edited by Offspring22
Posted

I’ve got the same issue. Feels like either the u-bolts in the axle have loosened up after a 163k miles or the trans mount or something is going out. It’s a very pronounced clunk coming from the drive train and only after sitting for several hours. 

Posted

Could be your leaf springs? But then again, mine clunk all the time...mostly first thing in the AM and when driving over pronounced bumps or potholes at a slow pace (i.e., parking lots).

  • 2 years later...
Posted

I have the same problem with my 2009 Sierra and if feels like  there is a delay in a solenoid that activates something in the torque converter to causes it so suddenly stop spinning and that jolts the vehicle.

Posted (edited)

try a trans re-learn from the dealer, and have them grease the splines on the output shaft yoke

 

 

these transmissions dont have acuumulators anymore, so if you got harsh shifts it could be due to a seal not holding pressure or the adaptations in the tcu are outta whack..  trans re-learn first

Edited by pokismoki

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
  • Latest Articles

  • Posts

    • The amount of storage in the rear seat area is huge. You can keep all your cycle gear dry and clean back there
    • Truck in fluid changes and investigate subtle shudder at cruising speeds.  Told them it felt like my ‘14’s shudder when AFM kicked in.   Dealer #1 :  You need a new torque converter.   6 weeks later, after causing other damages to my truck, I get the truck back.  Same shudder exists. New, more violent shifts and vibrations at low speed.  After choice words and a few more weeks of waiting for them to replace my running boards supports, I move on to another Dealer.   Dealer #2:  The cruising speed shudder is DFM.  (I didn’t realize truck had it.) The TCM/ECM needs updates.  Updates will solve all vibration issues.   They perform updates, truck seemed ok in lot.  Not a mile down the road, SERVICE BRAKE PAD MONITOR. Dealer #1 stated brakes were at 4mm.   took truck back to Dealer #2, rear brakes at 2mm and less than 1mm.     New pads/rotors on rear, new pads up front.   truck seems good. Toggle through menus, brake monitor system is disabled.  Huh?  Why? Turn that sucker on : SERVICE BRAKE SYSTEM!     will not reset manually, automatically, or even after pulling negative bat cable for 30min.     Could the TCM/ECM updates the culprit?    A torque converter diagnosis for a “normal” shudder and now I’m thousands in the hole and the truck still isn’t right!  Beyond pissed.  
    • Your right on. 👍🏻
    • Seats matter a lot.  I would start there - good advise here.  I had a 2018 LT Colorado before my 2026 LT Silverado, and the seats are so much better in the new one it's not even a contest.  That was one thing I always hated about the Colorado and I owned two of them spanning 10 years - but I did it so I could park in the garage mainly.  Now I have a much larger property and a huge barn so I have plenty of parking options and a full size is more useful for maintaining the property and current hobbies as well.  I wasn't evenb thinking about the seats as part of the reason for the move to the Silverado, but after two back to back 700mile road trips I am sold on the LT seats w/ leather 100%.  The other LT features are also nice - one thing I really like is the power rear window on the back window by the bed.  And the lighting in the bed is also very nice to have - I doubt that comes on the lower models.  Power tailgate - also quite useful - it's a heavy slug!  What else - I could take or leave the screen - but heated seats and steering wheel and cruise control on the steering wheel is very useable - I would never want to live without that.  Even the colorados had that.
    • I think the ship has sailed on the fuel injection type - everything is getting direct now.  Does it help with mpg?  Not really and nobody buying a HD truck really cares anyway.  But that is what it is at this point.  Piston rings is something they may well adjust over time to get them right.
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...