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8spd issues

David DeSouza
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CamaroVetteGuy Enthusiast

CamaroVetteGuy

Posted
Posted
On 1/1/2021 at 12:48 PM, UGADawgs said:

To describe it, it is like the truck goes to speed up and is then slightly being pulled back by tug rope and then it releases and it lunges and drives normally. 

I had a 17 Silverado with the 6 speed that did this. 

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BigMick2023
BigMick2023

2020 RST with 5.3 8-speed.... Zero issues with the transmission or otherwise......this truck has been flawless so far and never been back to the dealer.  Owned it for just shy of 1-year now.

SilveradoRST
SilveradoRST

Let us know if it improves the cold 1-2 hard shift.  

SilveradoRST
SilveradoRST

I know it’s an easy fix of a 5 minute warmup to avoid clunks.  But I would get the 10 speed just to avoid having to do that.  Would be nice to just get it and go in the mornings.     Wish they

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Swofford Enthusiast

Swofford

Posted
Posted

well, I have the truck back and I don't see any reason to back out (at least at this time).

The issue with the transmission hard downshift and a temp high-idle situation were caused when the dealership replaced a valve body on the transmission, when they found a slightly out of spec one during the GM pre-owned certification process (according to them). and apparently as part of the replacement, a software update to the TCM software is made. In this case, the software update did not complete successfully, causing the issue.  Once the update was applied and completed successfully, the transmission is as smooth as anything I have ever driven. Time will only tell if this is the total resolution for the future.

Additionally, the SRS messages and airbag light issue was a clock spring issue. They replaced the clock spring and no more message....

 

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flyingfool Senior Enthusiast

flyingfool

Posted
Posted

the software tune is the main issue in all the trans. they need reprogramming, its designed around highest MPG and maintaining low emmisions

  • 1 year later...
Phantom 4D Enthusiast

Phantom 4D

Posted
Posted

Cold hard shift seems to be an issue for sure. My truck had been sitting since Friday 2/4. The temps dropped at night in the low 20s. Monday 2/7 I got in to go run some errands. Shift from first to second was so hard it threw me forward. Second to third was hard but not as much as 1-2. the remaining shifts were a bit rough. Had the familiar hard downshift coming to a stop the rest of the day.  The fluid was change at the last service due to shifting issues. Didn't help. Aggravating.

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    • Chuck FB
      Tire psi

      By Chuck FB · Posted

      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. 
    • TrueBlue
      No Software Updates - Old Build

      By TrueBlue · Posted

      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?
    • jgaudet99
      Tire psi

      By jgaudet99 · Posted

      That's good to know, but I don't think I'll even be running them under 45 in the rear  unless it's on the sand or something but will only be for a short distance anyways!    I didn't read all the instructions in the booklet yet, but do you know let's say I set the rear psi on the placard to 45, will the warning light come on soon as it drops under 45 or is there a percentage it has to drop from the set value before the warning light is triggered?
    • newdude
      Would this CV Shaft be bad?

      By newdude · Posted

      That's bad.  Like, its probably destroying the stub axle the CV slides into.   Do you have a proper lift installed with differential lowering brackets?  Did you install AT4/Trail Boss factory CV axles?  
    • PunchT37
      Would this CV Shaft be bad?

      By PunchT37 · Posted

      Hot? New Jersey? Today? I was working on my old 2000 Silverado 1500 today. Believe me, it was boiling hot today. As it has been.

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