2018 with a stutter going uphills

[thekevin]

I have had my 2018 LTZ 5.3/6spd for 9 days now, its my first GM product since 2012.  I see lots of people on here complaining about the stutter during acceleration but I am seeing it a little differently.  I drive 50 miles a day on the interstate at 70mph.  When I hit hills it will switch seamlessly from v8 to v4 and then at random times it feels like a dead miss a couple of times and then it will normally downshift and then its fine the rest of the way up the hills.  It is really driving me crazy for a brand new truck to be doing this.  I love everything else about the truck but if it keeps this up I may light it on fire.

[B R A D]

If it's the stutter my last Sierra had you will notice the rpms bouncing when it does it.

Sent from my SM-N960U using Tapatalk

[thekevin]

I’ll pay attention to that over the few days. I have ran 4 tanks of gas through it so far. Whatever the dealer put in it when I bought it then 1 tank of e0 91, 1 tank of E85 and now back to e0 91.


Sent from my iPhone using Tapatalk

[2018GMC]

Is it lugging in v4 which causes the stutter then changes to v8 and it’s fine? You can try m5 for 6 speed or m7 if 8 speed which disables V4 mode. But at 70mph you prob want it in 6th or 8th What gears are in your truck? 

[thekevin]

It’s well after it goes back to v8. My truck is a 6spd with 3.42s. Once it downshifts into 5th it’s fine, it’s just the time before that when it’s trying to hold itself in 6th. It feels like a dead miss but I really think it’s transmission/converter related.


Sent from my iPhone using Tapatalk

[grizz_wi]

Same with my 2017 , i had a update applied and it fixed it maybe 80% i dont notice much unless i really try to look for it now.

[BigBadSierra]

Turn on the tow haul and see if it stops. This pumps up line pressure but adjusts the shift points.

 

This is not a fix just a test..  My truck as real issue deciding on what gear to use some days.

[300 Blackout]

It sounds like you’re throttle input is at the “sweet spot” for the trans to hesitate in downshifting as it climbs the hill. You know you’re going uphill and that you will be continuing to travel uphill. The computer in the trans is only dealing with actual data at the moment it receives it. If the trans downshifted every time it sensed increased resistance (going uphill, etc...) these forms would be filled up with people talking about how the trans shifts too much or burns out clutch packs too quickly.

The simple fix is to increase the trotted input to force the trans to downshift faster. This will get you into the correct gear quicker and the ride will likely be a lot smoother too.