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My new truck doesnt seem to shift correctly

paulv

By paulv
in Ask A GM Technician

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paulv Enthusiast

paulv

Posted
Posted

Hello,

 

I recentely just purchased a new 2012 Z71 Silverado to replaced my 1999 Silverado 2wd. The truck has wierd shifting habits that im really not certain to be abnormal or just me not liking the way it shifts.

But here goes.....

 

When I'm driving I can feel the transmission sometimes have hard upshifts @ 2nd-3rd and 3rd-4th. but almost always i feel it downshift . Mostly when off the accelerator from 35mph to 5 mph under light braking and sometimes from 50ish to stopping at a traffic ligtht. I know it has to downshift but I dont know why it does so pronounced. ( clunking at times ) I called the service manager at the dealer and he says the truck still needs to learn my driving habits.The truck has 2600 miles on it already so im not certain how much more it needs to learn. He also said they may have to reset it so it has to RE-learn my driving habits. I dont want to take it in unless absolutly necessary so i've been scouring the net looking for my answers.... I hope i can find them here.

 

Thanks,

Paul

Jsdirt Senior Enthusiast

Jsdirt

Posted
Posted

It's under warranty - let them deal with it.

 

That way if it decides to grenade at 10k miles and they refuse your warranty claim because, "you beat on it", or whatever excuse they deem necessary at the time .. you will have covered your rear. It's all documented in their computer whenever you bring it in.

CKNSLS Enthusiast

CKNSLS

Posted
Posted

The new 6 speed in these trucks are horrible. They should have never left the factory. To put it mildly, they are unrefined. Don't look for any GM fix IMHO. They are programmed for mpg, They clunk, bang, sloppy shift, etc.

 

Those things you and I mentioned are the most common complaints on the Chevrolet truck forums across the Internet!

 

You will get use to it-more or less.

 

Sorry Paul - there are no answers.

BlackZ71Silverado Senior Enthusiast

BlackZ71Silverado

Posted
Posted

The new 6 speed in these trucks are horrible. They should have never left the factory. To put it mildly, they are unrefined. Don't look for any GM fix IMHO. They are programmed for mpg, They clunk, bang, sloppy shift, etc.

 

Those things you and I mentioned are the most common complaints on the Chevrolet truck forums across the Internet!

 

You will get use to it-more or less.

 

Sorry Paul - there are no answers.

 

 

If you think there is no fix, you really don't know what you are talking about.

 

May sound suprising to you but there are answers............There is a TSB for the "clunk"/ "bang" by replacing the slip yoke with an updated nickle plated one. Clunking problem will be solved.

If you really don't like the sloppy shifting from the factory, that can be fixed with a tune. It will shift better and the transmission will run cooler. Real easy way to solve both problems.

 

OP, don't pay any attention to the response you got about no answers, they are easy fixes.

CKNSLS Enthusiast

CKNSLS

Posted
Posted

The new 6 speed in these trucks are horrible. They should have never left the factory. To put it mildly, they are unrefined. Don't look for any GM fix IMHO. They are programmed for mpg, They clunk, bang, sloppy shift, etc.

 

Those things you and I mentioned are the most common complaints on the Chevrolet truck forums across the Internet!

 

You will get use to it-more or less.

 

Sorry Paul - there are no answers.

 

 

If you think there is no fix, you really don't know what you are talking about.

 

May sound suprising to you but there are answers............There is a TSB for the "clunk"/ "bang" by replacing the slip yoke with an updated nickle plated one. Clunking problem will be solved.

If you really don't like the sloppy shifting from the factory, that can be fixed with a tune. It will shift better and the transmission will run cooler. Real easy way to solve both problems.

 

OP, don't pay any attention to the response you got about no answers, they are easy fixes.

 

 

A tune voids the warranty...that's not a viable fix if you wish to keep your 100K warranty, not to mention the cost. There is great debate about whether the ECM records a "change event" even if you tune it back to factory before taking it in to the dealership for work. You have to go through numerous channels and lubing of the yoke to get it replaced,

Jsdirt Senior Enthusiast

Jsdirt

Posted
Posted

I've got that clunk on my '07 as well. Has done it since it hit 2k miles. Greased the splines way back too - still does it.

 

It just serves as a reminder to me never to buy a new GM ever again.

waumo1 Enthusiast

waumo1

Posted
Posted

Yes the 6 speed auto is hashing and thrashing transmission. Add in the AFM in/out and things are weird.

However it has a lot more power/performance than my 98 did and gets about 20% better MPG and since it is a utilitarian

vehicle to me, I will live with it.

SouthCo Senior Enthusiast

SouthCo

Posted
Posted

My 6spd is not harsh at all. If anything, the shifting was too soft. I only hear a clunk sometime when I put it in reverse but my last toyota pickup did that too.

MikeNH Senior Enthusiast

MikeNH

Posted
Posted

In town I keep my truck in M4 or M5 depending on speed. Keeping it out of sixth prevents AFM from turning on and really helps responsiveness. And I'm not comfortable with tuning until I see an absolute answer on if GM can tell if the truck has been reflashed to stock from a tune. I'm probably being overly cautious though, tons of folks here love their BlackBear tunes.

 

 

Sent from my iPhone using Tapatalk

CKNSLS Enthusiast

CKNSLS

Posted
Posted

"No a tune does not void the warranty. You are misinformed.

 

 

Sent from my iPhone4S

using Tapatalk"

 

 

Please do tell us how going in and changing all the parameters the truck left the factory with will not void the warranty?

 

Please tell us why GM has issued a bulletin to it's dealers asking them to take a "snapshot" of the ECM readings when a truck comes in for service?

paulv Enthusiast

paulv

Posted
  • Author
Posted

I guess i will be taking it to the dealership. I really dont want to crack into a brand new transmission though. I have been driving the truck around to figure out what conditions the malfunction happens and came up with...... driving at 40mph and letting off the accelerator,as the truck slows down and down shifting starts occuring is when the truck has this clunk at each down shift. also when driving over 50 and braking somewhat agressive but not slamming the brakes.

 

I am not familiar with tuning stuff and wont pretend to know much about automatic transmissions. But i am a heavy equipment mechanic for some 20 years and know this just should'nt be like this.. This is my first 4wd truck and I am kinda bummed out despite getting a great deal on it.

CKNSLS Enthusiast

CKNSLS

Posted
Posted

I guess i will be taking it to the dealership. I really dont want to crack into a brand new transmission though. I have been driving the truck around to figure out what conditions the malfunction happens and came up with...... driving at 40mph and letting off the accelerator,as the truck slows down and down shifting starts occuring is when the truck has this clunk at each down shift. also when driving over 50 and braking somewhat agressive but not slamming the brakes.

 

I am not familiar with tuning stuff and wont pretend to know much about automatic transmissions. But i am a heavy equipment mechanic for some 20 years and know this just should'nt be like this.. This is my first 4wd truck and I am kinda bummed out despite getting a great deal on it.

 

 

Paul,

This transmission thing is all over the Internet and in various forums. Guys who are mechanics, engineers, etc., are some of the most dissatisfied because they would never let a design like this leave their desk. But the truth of the matter is they will most likely tell you that the transmission is "learning your driving habits".,etc. IMHO it's a software issue. But the "upside" if you will is that there have not been any massive failures with everyone experiencing problems like yours.

 

I would tell you just enjoy your truck and do what most of us have done (most quoted phrase in forums) "learn to live with it".

crankman Enthusiast

crankman

Posted
Posted

My 6spd is not harsh at all. If anything, the shifting was too soft. I only hear a clunk sometime when I put it in reverse but my last toyota pickup did that too.

 

IM with Southco my 2011 is so smooth never heard nothing. I would take it to the dealer asap.
hzhardy Enthusiast

hzhardy

Posted
Posted

"No a tune does not void the warranty. You are misinformed.

 

 

Sent from my iPhone4S

using Tapatalk"

 

 

Please do tell us how going in and changing all the parameters the truck left the factory with will not void the warranty?

 

Please tell us why GM has issued a bulletin to it's dealers asking them to take a "snapshot" of the ECM readings when a truck comes in for service?

 

 

If the tune you have or purchased is carb approved like the jet chip, GM cannot legally void your warranty. So if w/e part you place on your truck be it headers, exhuast, supercharger ect has gone to the EPA certification for carb you are fine.

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