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odd transmission shift

No Tyme

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No Tyme Senior Enthusiast

No Tyme

Posted
Posted

I have noticed the last couple of months that I have a high rev when my transmission shift from second to third. This only happens when after driving for a while, turning off the truck for a short time and then only the first sequence of shifts.

I want to make sure I am clear as when this happens... does not do it cold: only does it once after a short period of being shut down after a drive.

I don't abuse my truck and have never taken the truck off road... only off road is driving thru the yard to the barn... anyways It is a bit embarrassing with the louder pipes and I hope this isn't a sign of any issues to come.

Anyone else notice this?

Newell33 Enthusiast

Newell33

Posted
Posted

I'm not sure how high of a rev you're describing, but my truck does what I'd call a "flair shift" from second to third at random times. The rpm jumps up, and the shift takes a bit longer than normal. This has been discussed over multiple threads on this forum, and is pretty common with the GM trans tune (assuming you're not having a different issue). It seems random to me, and is another example of the poor transmission tuning on these trucks.

No Tyme Senior Enthusiast

No Tyme

Posted
  • Author
Posted

Well it's good to hear that I am not alone... But I do want to make it clear, I have no "tune" in my truck. It is stock from the factory. I assume you are talking about the GM computer tune in the ECM.

I did not do a search on this but certainly will now to see how this can be remedied. The longer it takes a trans to shift equals more wear and tear on components. Hopefully there is a fix other than custom tuning. :fingersx:

ccdies Enthusiast

ccdies

Posted
Posted

mine does the same, even with my tune it still does it

Silverado-Hareek Senior Enthusiast

Silverado-Hareek

Posted
Posted

I'm not sure how high of a rev you're describing, but my truck does what I'd call a "flair shift" from second to third at random times. The rpm jumps up, and the shift takes a bit longer than normal. This has been discussed over multiple threads on this forum, and is pretty common with the GM trans tune (assuming you're not having a different issue). It seems random to me, and is another example of the poor transmission tuning on these trucks.

 

Yes my truck does exactly this! I didn't really know how to describe it but you've worded it perfectly. It doesn't happen often but when it does it feels very weird and annoying.

Silverado-Hareek Senior Enthusiast

Silverado-Hareek

Posted
Posted

mine does the same, even with my tune it still does it

 

I don't have a tune but this makes sense because it seems to be related to how much throttle I'm giving it and it could be the truck sensing the throttle I'm giving it and how much fuel is being delivered to the engine, etc. and there's a hiccup in the computing of all of these parameters. To be clear, for me, it only does this when I push hard on the throttle to accelerate more quickly such as pulling out into traffic. It never does it if I'm taking it easy on the truck and my RPM's stay below 3,000 generally.

ccdies Enthusiast

ccdies

Posted
Posted

 

I don't have a tune but this makes sense because it seems to be related to how much throttle I'm giving it and it could be the truck sensing the throttle I'm giving it and how much fuel is being delivered to the engine, etc. and there's a hiccup in the computing of all of these parameters. To be clear, for me, it only does this when I push hard on the throttle to accelerate more quickly such as pulling out into traffic. It never does it if I'm taking it easy on the truck and my RPM's stay below 3,000 generally.

thats what i do, just try not to give it too much RPM at the shift point

  • 3 weeks later...
No Tyme Senior Enthusiast

No Tyme

Posted
  • Author
Posted

I took my truck into my dealership for this and was told they could not duplicate the issue. :dunno:

Well at least I know I am not alone. I was told by someone at the plant where these are made to run the trans through the gears in "trailering" mode and let the engine go up to 3500 rpms and see how firm the shifts are.

Then see how she shifts are after that in "D".

Basically I am monitoring the pedal pressure when that shift come up so I am not embarrassed when the engine takes a 500 rpm stroll. :eek:

Newell33 Enthusiast

Newell33

Posted
Posted

I had a nice flair shift experience last night. I turned onto a road near my home and put the pedal down almost all the way to the floor. The transmission flair shifted, but not the normal 2-500 rpm. It actually went all the way up to around 5,000 rpm before finally shifting. This was the first time it had flair shifted to that extreme. I was so disgusted that all I could do was burst out laughing. I guess it's all for mileage and the EPA, right?

crushNchowda Senior Enthusiast

crushNchowda

Posted
Posted

I know what you mean and I have only experienced it once or twice in 34,000 miles of ownership 5.3/3.42 truck w/ 6 speed. I had the "same" 6 speed more or less in my 2008 G8 GT and there was/is a well documented TSB concerning 2-3 "flare"/Harsh shift - in some instances only a computer flash was necessary, in others there was a procedure involving changing out clutch fluid seal rings, I know in the G8's some were installed "upside down" from the factory resulting in the flare

WendysOrBust Enthusiast

WendysOrBust

Posted
Posted

I have noticed the last couple of months that I have a high rev when my transmission shift from second to third. This only happens when after driving for a while, turning off the truck for a short time and then only the first sequence of shifts.

I want to make sure I am clear as when this happens... does not do it cold: only does it once after a short period of being shut down after a drive.

I don't abuse my truck and have never taken the truck off road... only off road is driving thru the yard to the barn... anyways It is a bit embarrassing with the louder pipes and I hope this isn't a sign of any issues to come.

Anyone else notice this?

Just shitty TCM programming done by GM

 

http://www.gm-trucks.com/forums/topic/172206-throttle-response-on-62/?p=1616390

f8l vnm Senior Enthusiast

f8l vnm

Posted
Posted

buddies 2008 5.3 Sierra runs and shifts like butter. His truck has over 140k on it.

What happened GM ? =(

WendysOrBust Enthusiast

WendysOrBust

Posted
Posted

buddies 2008 5.3 Sierra runs and shifts like butter. His truck has over 140k on it.

What happened GM ? =(

To be fair to GM, that is not an exactly new transmission.

thewhitestallion Senior Enthusiast

thewhitestallion

Posted
Posted

buddies 2008 5.3 Sierra runs and shifts like butter. His truck has over 140k on it.

What happened GM ? =(

 

He prob has the 4l80 (I think im sure someone will correct me if im wrong) and not the 6spd these trucks or the newer gmt-900 trucks have. my 02 5.3 trans had 200k original miles (hard miles) and it never skipped a beat. the 10 bolt was a different story though...

 

my truck also has this "problem". Plan on getting a black bear tune after I hit the 36k mark.

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