Jump to content

Recommended Posts

Posted

I have been trying to ignore the first shift or two every morning. This morning I backed out and thought let me give it some gas instead of light throttle like I normally do. It had a huge hestiation on that first shift to the point it felt like it went into neutral and my body actually lunged forward in the seat before it slammed into 2nd. Felt like a 16 year old bucking the clutch on a manual. After that first shift it was back to normal.


Sent from my Pixel 2 using Tapatalk

Posted
57 minutes ago, ShamrockShooter said:

I have been trying to ignore the first shift or two every morning. This morning I backed out and thought let me give it some gas instead of light throttle like I normally do. It had a huge hestiation on that first shift to the point it felt like it went into neutral and my body actually lunged forward in the seat before it slammed into 2nd. Felt like a 16 year old bucking the clutch on a manual. After that first shift it was back to normal.


Sent from my Pixel 2 using Tapatalk
 

What happens is and I know this from the Corvette forums over night the fluid drains back out of the torque converter so in the morning it just doesn't have enough fluid to give a proper shift. On the Corvette you can start the car first time and use the paddle shifter's to go from 1-2 and back again a couple times before selecting reverse or drive and doing this pressurizes the system enough to get a smooth 1 to two morning shift. Unfortunately we don't have this option on the trucks. You would think after 5 years GM would have come up with a fix for this.

Posted

It seems to be the worst when I park on my steep driveway engine uphill, then back out of the driveway. It hardly ever does it when it sits at work for 10 hours on level ground and put it straight into drive after startup. Also seems much worse when temp falls below 45.

But GM says it won't affect performance or longevity so we are forced to just accept it as is and move on as long as it only does it the first shift or two if the day.

Sent from my Pixel 2 using Tapatalk

Posted
8 minutes ago, ShamrockShooter said:

It seems to be the worst when I park on my steep driveway engine uphill, then back out of the driveway. It hardly ever does it when it sits at work for 10 hours on level ground and put it straight into drive after startup. Also seems much worse when temp falls below 45.

But GM says it won't affect performance or longevity so we are forced to just accept it as is and move on as long as it only does it the first shift or two if the day.

Sent from my Pixel 2 using Tapatalk
 

Start parking backwards on your inclined driveway. ? 

 

I backed into my inclined driveway and parked over night last night (not to help the trans, just for some other reason), and I actually noticed my shifts were SUPER smooth this AM. 

 

So yeah, maybe this has something to do with oil getting into the torque converter? 

Posted
Start parking backwards on your inclined driveway. [emoji16] 
 
I backed into my inclined driveway and parked over night last night (not to help the trans, just for some other reason), and I actually noticed my shifts were SUPER smooth this AM. 
 
So yeah, maybe this has something to do with oil getting into the torque converter? 
So there you all go. I solved the problem. That was easy.

Sent from my Pixel 2 using Tapatalk

Posted
On ‎4‎/‎29‎/‎2019 at 6:39 PM, Bmwtech113 said:

I have a 2019 AT4 with the 5.3l engine. I’ve had it for about a month now and I have noticed especially when I first take off after the truck has been sitting for a few hours that there is a jolt that will happen multiple times while accelerating up to speed. I’m not flooring it, just accelerating normally. It occurs between 10 and 50 mph and once it warms up then I never notice it again. Happens in D and also if it put it in L7 or L8. It feels like either a misfire or the transmission slipping. I just picked it up from my dealer tonight after they said “we’ve had other complaints but that’s just how it is.” 

Has anyone else experienced this?

You should have "firm" shifts on warm up...after that it goes away?  It should even be stated in your manual I believe has to do with warming the fluid up quicker and reducing wear on components....

Posted
2 hours ago, mookdoc6 said:

You should have "firm" shifts on warm up...after that it goes away?  It should even be stated in your manual I believe has to do with warming the fluid up quicker and reducing wear on components....

My main issue has nothing to do with shifting. Maybe I am describing it inaccurately but it is like a transmission slip that occurs multiple times over the course of a few seconds or like a stutter. It happens during acceleration from around 10mph up to 50 mph but not at shift points. If it were an all-wheel drive BMW I would say it feels exactly like the transfer case is slipping but I'm not sure the 4x4 system on these trucks works the same as the BMW all-wheel drive system.

Posted
Start parking backwards on your inclined driveway. [emoji16] 
 
I backed into my inclined driveway and parked over night last night (not to help the trans, just for some other reason), and I actually noticed my shifts were SUPER smooth this AM. 
 
So yeah, maybe this has something to do with oil getting into the torque converter? 
Nope. Backed in last night. Still had hard 1-2 shift this morning.

Sent from my Pixel 2 using Tapatalk

Posted
51 minutes ago, ShamrockShooter said:

Nope. Backed in last night. Still had hard 1-2 shift this morning.

Sent from my Pixel 2 using Tapatalk
 

Well that's disappointing. At least you tried! 

 

My 8 speed has been unusually amazing the past week. I'm not sure if it knows how badly it's being talked about or what. Lol 

Posted

Ever since the new fluid, I have not had the exact issue I originally had which was when going up a hill on a cold start the drivetrain would jolt or buck about 3 or 4 times in about a 5 second span. 

I took the truck back this past Saturday for a harsh 1-2 and 2-1 shift. They basically told me it was normal and I have to admit the loaner truck felt the same at times as far as the 1-2 and 2-1 shifts. 

However I still get a random jolt from the drivetrain. It doesn’t appear to be when shifting but it is at lower speeds between 10-50mph. The drivetrain on this truck in general feels like at times it doesn’t know what it wants to do and gets confused causing a rumble or clunk type feeling. Some of that may or may not be the DFM. One thing I did notice is that on the loaner they gave me (a Silverado LTZ 5.3) the engine rpms seemed to stay higher than what the rpms are at the same speeds on my AT4. 

Posted

Well I spoke too soon about my original issue being fixed. It happened today. Going about 15-20mph through a neighborhood at constant throttle I felt a shudder and could even see the rpms fluctuating as it was happening. I’ll be back in touch with GM tomorrow. 

Posted

mine does it to, also seems to take a couple seconds to go from reverse to drive, after the first 40 feet its fine.

 

  • 5 months later...
  • 2 weeks later...
Posted
On 4/29/2019 at 8:39 PM, Bmwtech113 said:

I have a 2019 AT4 with the 5.3l engine. I’ve had it for about a month now and I have noticed especially when I first take off after the truck has been sitting for a few hours that there is a jolt that will happen multiple times while accelerating up to speed. I’m not flooring it, just accelerating normally. It occurs between 10 and 50 mph and once it warms up then I never notice it again. Happens in D and also if it put it in L7 or L8. It feels like either a misfire or the transmission slipping. I just picked it up from my dealer tonight after they said “we’ve had other complaints but that’s just how it is.” 

Has anyone else experienced this?

I have the same exact problem with my 2019 GMC Sierra.

The dealer told me GM will not pay for any repairs on this. UNBELIEVABLE ! 

I would never by another GM product and I suggest otherS to beware. 

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
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Forum Statistics

    250.5k
    Total Topics
    2.7m
    Total Posts
  • Member Statistics

    342,965
    Total Members
    8,960
    Most Online
    DaleB
    Newest Member
    DaleB
    Joined
  • Who's Online   3 Members, 0 Anonymous, 1,100 Guests (See full list)


  • Latest Articles

  • Posts

    • Common Sense Assembly   Your driveline is forgiving of the occasional mistake. It will even often forgive the random serious blunder. But it will not forgive a continuous bad habit.      What? Not everything needs to be a five thousand word essay.       
    • We drove about 15 minute east today to visit a friend and saw a steep increase in price in the same county. About 50 cents a gallon steepper. 
    • Sure about that? A degree wheel and a dial indicator would lower your degree of assurance in that statement. 😉    It why we have offset keys and dialable timing sprockets. Just say'n.... I've built a few and have never seen one "On the money". 
    • I will admit I haven't experimented much with pressure drops beyond the numbers I put in and part of that is that the numbers I used are fairly low and then found out it would trigger regardless at that 35 psi. Having said that I had tried before had changed the placard pressures and being that I have a 1 ton set to 80 on the placard for the rear I believe it triggered close to 60, the front I don't recall now for sure but thought maybe it could get close to 45 from that factory 60 placard pressure. So I never did figure out if it was a number of psi from placard pressure to the alarm or a percentage of the total placard number as some figured it was like a 25% drop from placard pressure would trigger it. So as to try and answer your question, I believe I set the placard pressure on the front to 47 or so and while I run the front tires at 40, they have dipped below that some if its colder and I haven't put "winter air" in yet and never once have had the front alarm go off. I would say that the answer your looking for is no, that if you set your placard pressure to 45, you have a certain amount of room to drop below that pressure before the alarm will go off.    The pressures you decide to run in your truck, that ends up being what makes sense to you based on what your carrying in your truck or if towing, then have to bump them back up to something that will carry the load in the rear and the fronts typically left at the same pressure. It all comes down to that chart I put the link to and using an accurate roadside scale to be your guide, both unloaded and then loaded to know your minimum safe pressures.    I just wish GM would allow a person to change the readings for the tire pressures to the English system of pounds as I have to look at that goofy metric reading that will never ever jive in my head and will go over and change it just to figure out what they are if need be and then change it back. 
    • That part I understand, that the dealer can do it. But I'm not understanding why updates that were available to the truck since it left the factory, or the dealership originally, would not still be available to it without dealer intervention.   I'm thinking along the lines of recalls. They stay available until they are completed, regardless of whether they are in warranty or not, or in the hands of the original owner or not. Why not updates as well, especially since some of those can be safety related also?
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...