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6 speed hard shift persistent issue

Kspinazzola
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Kspinazzola Enthusiast

Kspinazzola

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Well guys I wanna start my saying sorry, I’m sure this issue has been beat to death but I still can’t figure it out. 
my 5.3L 2014 Silverado crew cab lt 6 speed shifts hard and won’t stop. Pretty much only on downshifts. Usually 3-2 is hard, 2-1 is always hard every time. And if I floor it or go up a hill fast, it’s always hard. I bought a hypermax 2000 max energy 2.0 tuner. I mess with the shift points and shift firmness but can’t get the hard shifts to go away. Does anyone know where to set the shift points to get it smooth?

 

if not then does anyone know a tuner or tuning service that can 100% get rid of the hard shifts?

 

my truck is literally so perfect except for the shifting, but it’s driving me mad. 
ive been a huge GM guy for the longest time but if I can’t fix this I’m gonna switch to a dodge or ford which is disappointing to me. GM should have done something about this. 

Edited by Kspinazzola
swathdiver Senior Enthusiast

swathdiver

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Posted
2 hours ago, Kspinazzola said:

...if I can’t fix this I’m gonna switch to a dodge or ford which is disappointing to me. GM should have done something about this. 

Since when are ALL the trucks doing this?  Just yours so focus on that and why.  What happens when you remove the tuner?  What are the line pressures?

Bash74 Enthusiast

Bash74

Posted
Posted

What do you mean by hard? I ask because a good hard shift is what I prefer over some laggy gentle shift.

Sent from my SM-G975U1 using Tapatalk

Kspinazzola Enthusiast

Kspinazzola

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15 hours ago, Bash74 said:

What do you mean by hard? I ask because a good hard shift is what I prefer over some laggy gentle shift.

Sent from my SM-G975U1 using Tapatalk
 

I mean I get a jolt in the whole truck when shifting,

Kspinazzola Enthusiast

Kspinazzola

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21 hours ago, swathdiver said:

Since when are ALL the trucks doing this?  Just yours so focus on that and why.  What happens when you remove the tuner?  What are the line pressures?

I’m not saying all of them did it but it’s a well documented semi common issue that plagued a lot of these 6 speeds and I haven’t seen anyone find any real fixes for it except a few people who say they were able to fix it by changing shift points so that’s what I was hoping to do. I don’t know the like pressures but I’ll look into finding that out in the morning. 

swathdiver Senior Enthusiast

swathdiver

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Posted
3 hours ago, Kspinazzola said:

I’m not saying all of them did it but it’s a well documented semi common issue that plagued a lot of these 6 speeds and I haven’t seen anyone find any real fixes for it except a few people who say they were able to fix it by changing shift points so that’s what I was hoping to do. I don’t know the like pressures but I’ll look into finding that out in the morning. 

Ok, first I've heard of this.  I have the same transmission in the previous generation.  Anyhow, have you owned the truck since new?  How many miles are on it and when was the transmission serviced last?

Kspinazzola Enthusiast

Kspinazzola

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On 6/26/2020 at 6:28 AM, swathdiver said:

Ok, first I've heard of this.  I have the same transmission in the previous generation.  Anyhow, have you owned the truck since new?  How many miles are on it and when was the transmission serviced last?


I bought the truck last year with 120K and now has 140K so it does have some miles on it. It’s been shifting hard since I bought it. I was told by a lot of people on different forums that the tranny hard shifts for this generation we’re usually caused by the ECU shift points being tuned for fuel efficiency, so I was advised to buy a tuner and change the shift points to fix it, but it’s pretty much done nothing so far. 

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Kspinazzola Enthusiast

Kspinazzola

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On 6/26/2020 at 2:10 PM, Grumpy Bear said:

Sounds like a hardware issue, not software. 

Yes I’m starting to agree with this. At first I was told lots of times it’s due to the tuning of the tcm but after custom tuning nothing has changed. I’m starting to think somethings broken 

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  • 4 weeks later...
Kspinazzola Enthusiast

Kspinazzola

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On 7/2/2020 at 10:06 AM, swathdiver said:

Have you changed the fluid?  If so, what method and what fluid was used?

I actually haven’t, I checked it when I bought it (125K) and the level was fine, so I left it alone But when I checked it I used a dirty rag and didn’t see the color. When I checked a week ago I noticed the color was pretty dark. So I’m changing it a few quarts at a time to see if it helps any. Idk if it will but I figure clean fluid won’t hurt. I don’t wanna drop the pan so I pumped out 2 quarts the other day and replaced 2 quarts. I’m gonna do the same thing every couple weeks until at least half is new then wait a few months since GM doesn’t recommend a full flush.

  • 4 weeks later...
swathdiver Senior Enthusiast

swathdiver

Posted
Posted
On 7/27/2020 at 10:28 PM, Kspinazzola said:

I actually haven’t, I checked it when I bought it (125K) and the level was fine, so I left it alone But when I checked it I used a dirty rag and didn’t see the color. When I checked a week ago I noticed the color was pretty dark. So I’m changing it a few quarts at a time to see if it helps any. Idk if it will but I figure clean fluid won’t hurt. I don’t wanna drop the pan so I pumped out 2 quarts the other day and replaced 2 quarts. I’m gonna do the same thing every couple weeks until at least half is new then wait a few months since GM doesn’t recommend a full flush.

The GM shop manuals show as SOP a complete fluid exchange using the TransFlow machine.  They also test the external transmission coolers for obstructions or reduced flow.  Since yours has a thermostat and runs at 195+ all the time, the severe service schedule should be followed.  I sent a sample of mine to Blackstone Labs for analysis and at 36K miles with about a week of towing on it, the fluid was said to have only about 10K miles of life left.  Needless to say, my new service interval will be about 36K from now on.  

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