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6 Speed Transmission Issues

Ohiozr2

By Ohiozr2
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Ohiozr2 Enthusiast

Ohiozr2

Posted
Posted

My transmission appears to be shuddering when cold. Is there a TSB for any issues with the 6 speed? The dealer told me that they cannot do anything if there are not any codes being thrown.

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1SLOW1500
1SLOW1500

slip over demand. It can be tuned out. 

DeePa
DeePa

Just took it for a 55 mile or so test drive. It’s always an uneasy feeling to drop 500 bucks not really knowing what the results could be.    This truck is so much smoother and more relaxing

swathdiver
swathdiver

The 6-speeds were fine until they put them in your K2s.  GM added a thermostat which keeps the trans temps up at 195 all the time, which makes Uncle Sam happy but kills these transmissions by 100K mil

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aero10 Enthusiast

aero10

Posted
Posted

Mine does it, especially going up hill at low RPM. I've had no success getting it fixed. Luckily it doesn't happen much, so I just love with it.

Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted
35 minutes ago, Ohiozr2 said:

My transmission appears to be shuddering when cold. Is there a TSB for any issues with the 6 speed? The dealer told me that they cannot do anything if there are not any codes being thrown.

I've never had an automatic that wasn't a little flaky when it gets really cold outside and from every manufacture. Clears up in a few minutes when the fluid warms a bit. Does that should like yours? 

Capt Bob Enthusiast

Capt Bob

Posted
Posted

Mine is the same. With the cold weather rolling into Tallahassee and a fairly steep grade leaving my neighborhood I too experience that slight shudder early on. Clears up rather quickly. You should be fine.

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Ohiozr2 Enthusiast

Ohiozr2

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20 minutes ago, 1SLOW1500 said:

slip over demand. It can be tuned out. 

Do you have any more info on this? A link, etc. is it “normal”, as in it won’t get worse and the transmission isn’t going out?

Ohiozr2 Enthusiast

Ohiozr2

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1 hour ago, Grumpy Bear said:

I've never had an automatic that wasn't a little flaky when it gets really cold outside and from every manufacture. Clears up in a few minutes when the fluid warms a bit. Does that should like yours? 

For the most part, it pauses between 2nd-3rd for maybe 3-4 seconds on the first shift of the day. Just trying to figure out if it is actually normal or not.

1SLOW1500 Senior Enthusiast

1SLOW1500

Posted
Posted
Do you have any more info on this? A link, etc. is it “normal”, as in it won’t get worse and the transmission isn’t going out?
Yeah normal. When you see the temp tables there is so much in there that the truck isn't running normal till 180*+.
It could be worst. If you are the type of person that notices these things. One day drive full throttle and let off there is fuel shut off. Then the v4 mod the the shifts then the slip. Lot going on.
The trans has to slip or the engine needs to dum down the power. So you almost never get the power you think. It is reduced and the tables are set for unrealistic peramitor like over 5000rpm at full throttle in 3rd gear for more than so many seconds.
That is why we tell people in tune it makes the truck a whole new truck. But number one thing I hear is X shop tuned it and it drive bad and shifts slow....i ask if they tuned the trans.
And GB is right there is a optimal temp for tran fluid. Cool is bad but past optimal is also damaging.

Sent from my SM-N960U using Tapatalk

Ohiozr2 Enthusiast

Ohiozr2

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3 minutes ago, 1SLOW1500 said:

Yeah normal. When you see the temp tables there is so much in there that the truck isn't running normal till 180*+.
It could be worst. If you are the type of person that notices these things. One day drive full throttle and let off there is fuel shut off. Then the v4 mod the the shifts then the slip. Lot going on.
The trans has to slip or the engine needs to dum down the power. So you almost never get the power you think. It is reduced and the tables are set for unrealistic peramitor like over 5000rpm at full throttle in 3rd gear for more than so many seconds.
That is why we tell people in tune it makes the truck a whole new truck. But number one thing I hear is X shop tuned it and it drive bad and shifts slow....i ask if they tuned the trans.
And GB is right there is a optimal temp for tran fluid. Cool is bad but past optimal is also damaging.

Sent from my SM-N960U using Tapatalk
 

Interesting, it does seems worse on days I have to get on it quicker, but I can still notice when I don’t have to. The road I have to turn on isn’t ideal. As long as it isn’t going to deteriorate, I can deal with it.

1SLOW1500 Senior Enthusiast

1SLOW1500

Posted
Posted
1 minute ago, Ohiozr2 said:

Interesting, it does seems worse on days I have to get on it quicker, but I can still notice when I don’t have to. The road I have to turn on isn’t ideal. As long as it isn’t going to deteriorate, I can deal with it.

yes and no. the v4 mod with the afm and dod is bad news. the oil consumption is bad news also. the trans is tuned to band aid those issues. It will always be called a opinion even is GM says it. Like the people arguing for the more oil vs. GM notice that 8 is the max.  but best to look into and mod to get away from those issues. 

Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted

I haven't got eye in the program like 1SLOW1500 so I don't know what I don't know. What I do know is that above 100F my transmission is about as perfect as a mechanical device can be. Yes I notice the slight 'bump' in rpm between shifts but only if I'm watching the tachometer. Some see this as a negative. 

 

Before the days of TCM when automatics were shifted on vacuum and a governor there was programed into the hydraulics the condition where as the first gear clutch was disengaging the second gear band was starting to apply. Meaning for a fraction of a second you were both in first and second gear. They only thing that kept the box from breaking was 'slip'. But it didn't show up on the tachometer. It just felt like a very smooth shift. It would repeat going for the second gear band to the high gear clutch pack. This created excess friction that given enough time wore out clutches and bands. Companies like B&M made shift kits that eliminated or reduced this over lap and increased line pressures. The result was lower wear but a fairly abrupt shift and if you had your foot in it, it might bark the tires pretty good even if the motor powering it was under 200 hp. and the car over 3500 pounds. Either way, people complained and wear was traded for component failures and happy teenagers. Converters didn't have lock up clutches and slip overheated transmission fluids when towing or if stall speeds were too high. We added coolers and low slip fluids much like the old Ford Type F. Honda still uses a variant. B&M called theirs Trick Shift. 

 

So now we have a computer calling the shots and between gears the motor is allowed a bit of freewheeling, slip over demand, and to keep it from feeling like a train hits you each shift the timing and fuel are cut to reduce torque, thus called torque management. People hate that too. 

 

Bottom line every possible combination has been tried and all that changes is which people get happy. Yes a tune might improve your personal perception and tailor the shift to your specific taste. Question becomes...will the rest of the drive line like it? One of the things I love about machines is that they will do what they are told. :) 

 

Obviously a transmission must be able to work acceptably at any temperature it is expected to see and yes this includes

-50F to 300F. What isn't expected is that it remain at either extreme for more than a transitory time. We still use coolers to clip the upper limit and now a thermostat to cap the lower limits of 'normal' operation. Do they get it perfect? Depends our likes and dislikes doesn't it? 

 

This is just offered as some additional material to help you determine what might be okay and what could be an issue requiring professional attention. We are not there and we are not living with it. 

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swathdiver Senior Enthusiast

swathdiver

Posted
Posted
8 hours ago, 1SLOW1500 said:

That is why we tell people in tune it makes the truck a whole new truck. But number one thing I hear is X shop tuned it and it drive bad and shifts slow....i ask if they tuned the trans.

The best part of my BlackBear tune was what Justin did to the transmission, she runs fantastic, cold, hot doesn't matter.

  • Like 1
batman900 Enthusiast

batman900

Posted
Posted

I have the exact same issue OP. It drives me nuts for the first few min every morning and when leaving work, especially now that its winter. I also have an up hill on ramp 1 mile from my house to the hwy, whooo this thing bucks. Smooth as butter once shes warmed up.

 

As a side note, I just got my wife a new 2019 Camry SE, 8 speed 4 cyl. I had to drive it yesterday and take my kid to school so I could go get her tint done. It was 18F and when it would shift it would kind of buck/bounce like in a manual transmission that got shifted too soon, it did this every gear until warmed up. Was kinda funny and made me feel better about my truck. Older autos never had these issues, it's like others have said I guess, a combo of all the computers and trying to run at 1000-1100 rpm even when accelerating. The tuning in these new vehicles really lugs the engines.

Sierra Dan Senior Enthusiast

Sierra Dan

Posted
Posted

The transmission is often blamed for instances when AFM goes haywire and is actually the culprit.

Try shifting to M5 disabling V4 AFM and see if your shuddering continues.

13 hours ago, Ohiozr2 said:

My transmission appears to be shuddering when cold. Is there a TSB for any issues with the 6 speed? The dealer told me that they cannot do anything if there are not any codes being thrown.

 

batman900 Enthusiast

batman900

Posted
Posted
10 hours ago, Sierra Dan said:

The transmission is often blamed for instances when AFM goes haywire and is actually the culprit.

Try shifting to M5 disabling V4 AFM and see if your shuddering continues.

 

I tried the range and disabled Afm but it didn’t make any difference with this issue.

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