issue Transmissions Issues/Problems

Dixon700 · May 9, 2016

Is this just a'14 and newer issue? My uncles '13 with the 6 speed seems to shift pretty normally. My '02 on the other hand occasionally shifts real hard.

No Tyme · May 11, 2016

My 14 CC 4X4 started having shift flares after 5,000 miles and the TCM replacement did not help. I had to have the tranny tore out, the 3,5,R clutch drum replaced and that took care of my shift flares.

Now on a side note there is another thread that I am following that many are getting improved MPG's and seeing the transmission actually shift better by just disabling the "grade braking" each time you start the truck. To do this after your engine is running just hold the two/haul button in for 4 or 5 seconds and make sure you get the message in the DIC that it has been disabled.

Like I stated there is another thread that many have posted improved results by doing this.

http://www.gm-trucks.com/forums/topic/186752-interesting-progress-with-odd-trans-behavior-2015-6-speed/

kfjethro · May 12, 2016

"I really hate my truck" - That's what I tell friends/acquaintances who ask me how I like my truck. Unfortunately it's the truth, It's got all kinds of problems (seats, springs, transfer case, radiator smell, etc) but the worst is the transmission / drive-line. It's so bad it takes all of the enjoyment out of driving. Even if GM eventually fixes my truck before the warranty is off, I'm probably done with GM. They can't make seats or springs - how are they going to make a transmission ?

One transmission behaviour that I didn't see in the 19 pages of this thread (I may have missed it) is that my truck sometimes upshifts while braking. If I prepare for a turn by just letting off the gas pedal, the truck will shift down, and start to slow down due to back pressure like it should. I then apply some continuous brake until I'm at a good speed for the turn. Sometimes, the transmission will suddenly upshift (I think that's what it is doing) and the truck's speed will increase forcing me to brake much harder to slow down for the turn. The first time it happened I almost went by my turnoff. This is at city speeds.It's kind of like when a manual shift transmission pops out of gear unexpectedly. Is this normal behaviour ?

andyhaug · May 12, 2016

I have experienced this as well. I think it is while braking the transmission downshifts, because the RPMs are too low, and when it gets to the next gear the dynamic braking is less resulting is a feeling of less braking. Or the truck downshifts and during the downshift process it disconnects from the gear then revs the engine before going to the next gear, when engaging the next gear the engine is spinning too fast resulting in a little acceleration.

I have experienced the push feeling with my first transmission, I am on #2 now. A couple of times when braking to a stop light, it felt like I lost a bunch of braking force, either by loss of braking force from the transmission or the transmission pushing me.

I think I experienced the second scenario a couple of weeks ago when I was coasting behind a truck coming to a stop light. I was not touching either pedal and the truck gave me a little acceleration toward the back of the truck in front of me, not a good feeling. Dealer informed me that it was my opinion that it was wrong. Pretty sure there have been many issues in the past with manufacturers and uncontrolled acceleration.

I would not consider this normal. Anytime this thing does something I am not asking it to it pisses me off. I am in the same boat where I hate my truck. I really wish I had the 2000 Silverado, that I traded in, back but I am stuck with this now. I have tried a different dealer and they seemed helpful at first, but now they will not call me back. You could try disabling grade braking by holding in the tow/haul button for 5+ seconds, it does seem a little better but is not the entire solution. See the thread in the previous post.

kfjethro · May 13, 2016

Thanks Andy. I had it totally backwards - it's the gas blip before the downshift. My other vehicle is a manual shift and that's exactly what I would do if I were shifting down to slow down. I never noticed this in an automatic before but perhaps it is the grade braking. I'll disable it and see if there is any difference. Thanks again.

kfjethro · May 17, 2016

Disabling the grade braking seemed to allow the truck to coast better for a better driving experience, but the clunks are still there. I don't do much highway driving but it seems that the transmission works better after a 50-75 km drive on the highway (better coasting and fewer clunks). Do these clunks hurt the transmission ?

HondaHawkGT · May 17, 2016

Disabling the grade braking seemed to allow the truck to coast better for a better driving experience, but the clunks are still there. I don't do much highway driving but it seems that the transmission works better after a 50-75 km drive on the highway (better coasting and fewer clunks). Do these clunks hurt the transmission ?

No the clunks won't hurt it.

Silvz06 · May 18, 2016

I own a 2015 silverado 5.3 and can't stand the way it shifts. I drove a 2016 and it felt much better, night and day. Must be that new 8 speed that helped. I can't wait for a nice tune.

mjj · May 18, 2016

No the clunks won't hurt it.

What exactly is making that clunking sound?

MyakkaLivin · June 8, 2016

My 14 CC 4X4 started having shift flares after 5,000 miles and the TCM replacement did not help. I had to have the tranny tore out, the 3,5,R clutch drum replaced and that took care of my shift flares.

Now on a side note there is another thread that I am following that many are getting improved MPG's and seeing the transmission actually shift better by just disabling the "grade braking" each time you start the truck. To do this after your engine is running just hold the two/haul button in for 4 or 5 seconds and make sure you get the message in the DIC that it has been disabled.

Like I stated there is another thread that many have posted improved results by doing this.

http://www.gm-trucks.com/forums/topic/186752-interesting-progress-with-odd-trans-behavior-2015-6-speed/

I have a '15 Sierra 5.3 6sp and disabling the Grade Braking didn't do a thing...and believe me I was hoping it would work. Did a little research and found the disabling the Grade Breaking only works when you're in the Tow/Haul mode, which is fine but expect your mpg's to suffer. I tried it and the tranny never shifted into fifth gear(?) Maybe it would if I drove faster than 60 mph but driving around town the engine never ran less than 2000 rpm.

WLC · June 11, 2016

Tranny quit pulling today and coasted to a driveway and shifted to neutral then back to drive and worked again.Glad I wasn't going up one of the big hills around. Wife asked what's next with these trucks? Did not have an answer for her.Ideas???

andyhaug · June 16, 2016

Had another chat with GM CAC again today, I was irritated enough afterward to take the truck out and beat on it a little. I normally drive pretty conservative, trying to get as good of mileage as it will get. The struggle I have is I cannot get the truck to respond when I need it to get out of the way. I was doing some hard braking followed by hard acceleration. I was doing maybe 40 MPH when I slammed on the brakes then immediately went to the gas at maybe 5 MPH. I was barely able to get it to 25 MPH and bouncing off the rev limiter, no wheel spin, no traction control problems or anything, the truck would not simply not get out of it's own way. How is this normal? I should have been going like a bat out of hell! Is there any hope GM will ever fix this? Should I just get a tune,write off GM, and be done with this? Does any other manufacturer do any better? I am very disappointed in this truck, why can't it just do what I am telling it to do with the pedals? Vehicles have been doing this for 100 years, why is it a problem now? I am really at a loss here, what should I do with this POS?

nadrojcote · June 16, 2016

Had another chat with GM CAC again today, I was irritated enough afterward to take the truck out and beat on it a little. I normally drive pretty conservative, trying to get as good of mileage as it will get. The struggle I have is I cannot get the truck to respond when I need it to get out of the way. I was doing some hard braking followed by hard acceleration. I was doing maybe 40 MPH when I slammed on the brakes then immediately went to the gas at maybe 5 MPH. I was barely able to get it to 25 MPH and bouncing off the rev limiter, no wheel spin, no traction control problems or anything, the truck would not simply not get out of it's own way. How is this normal? I should have been going like a bat out of hell! Is there any hope GM will ever fix this? Should I just get a tune,write off GM, and be done with this? Does any other manufacturer do any better? I am very disappointed in this truck, why can't it just do what I am telling it to do with the pedals? Vehicles have been doing this for 100 years, why is it a problem now? I am really at a loss here, what should I do with this POS?

My new Ford responds like a dream. I tried a tune like everyone said on this forum, but in the end there is nothing that could fix the poor response of the new GM's. Take another manufacturer out for a test drive and I bet you won't be disappointed.

Raudulfr the Fearsome · June 20, 2016

Hello TexasRadar,

We recognize your frustration, and apologize that your transmission concerns haven't been fully resolved. We'd like to investigate this matter further for you and work towards possibly addressing your concerns. If this interests you, please private message us your full contact information, VIN, current mileage, and the name of your dealership.

Thank you,

Amber N. (assisting Jennifer & Kristen)

GM Customer Care

Yup, I bought my 2015 Silverado in february and people ask me every week how I like my brand new truck..so I am honest with them and let them know I really hate it.

As described above mine when travelling 50kph and I slow down to turn a corner and god forbid its an uphill road the thing dogs down like its running out of gas until i stop the pedal to the floor ....then BAM its down to 2nd, up to redline and tires squealing like a 17 year old. Tried to merge onto the highway the other day, same story, have an opening in traffic and accelerate as you would in a NORMAL vehicle and ....nothin...here comes the highway traffic and again, foot has to hit the floor to get it to do anything. Without question the worst truck to choose if you work for a living. Mine in a WT edition...I needed it for WORK...so I put on a canopy, 2 ladders and a wooden shelf in the back and there is was, sagging in the rear about 4" lower than the front. Took it into the dealer and their answer was "oh well its just too much weight for it to be level" WHAT? I have under 500lbs in my work truck and I am getting people flashing me thinking I have high beams on because my truck isn't level. Had to go and have a $700 leaf spring kit just to fix my 4 month old truck.

Then there is the fuel pump vibrating so hard when I open the door that it actually rattles the dash

And of course there is the dieseling...due of course to the truck shifting into 6th gear going 30kph. I was again, working with my work truck, and heading up a VERY steep driveway and it went from 1st to about 5th then it was like I was driving a truck built in 1967 with a 3 speed..dieseling up the hill, wouldn't shift out until you pound the pedal again...of course leading to such a hard shift like a loud CLUNK it knocked my cel phone mount off the dash.

OH, last thursday turning a mild left corner my drivers side rear tire is skipping and chirping because its like its locked in 4wd but it wasn't. Went down and turned the truck around, more chirping..and it hasn't done it again in the last 4 days.

Have had to do 2 emergency stops now and both times when I went to accelerate nope..nothing at all...stalled cold.

Its going into the dealer AGAIN tomorrow which I am certain I will be met with "Well they are just another kind of animal and you have to get used to it"

45 grand and I have a truck that is probably the worst driving vehicle I have ever owned. It currently has 7200kms on it. Pretty sure I paid for a TRUCK, not a gas sipping grocery getter.

Sincerely a very displeased client

HondaHawkGT · June 21, 2016

Yup, I bought my 2015 Silverado in february and people ask me every week how I like my brand new truck..so I am honest with them and let them know I really hate it.

As described above mine when travelling 50kph and I slow down to turn a corner and god forbid its an uphill road the thing dogs down like its running out of gas until i stop the pedal to the floor ....then BAM its down to 2nd, up to redline and tires squealing like a 17 year old. Tried to merge onto the highway the other day, same story, have an opening in traffic and accelerate as you would in a NORMAL vehicle and ....nothin...here comes the highway traffic and again, foot has to hit the floor to get it to do anything. Without question the worst truck to choose if you work for a living. Mine in a WT edition...I needed it for WORK...so I put on a canopy, 2 ladders and a wooden shelf in the back and there is was, sagging in the rear about 4" lower than the front. Took it into the dealer and their answer was "oh well its just too much weight for it to be level" WHAT? I have under 500lbs in my work truck and I am getting people flashing me thinking I have high beams on because my truck isn't level. Had to go and have a $700 leaf spring kit just to fix my 4 month old truck.

Then there is the fuel pump vibrating so hard when I open the door that it actually rattles the dash

And of course there is the dieseling...due of course to the truck shifting into 6th gear going 30kph. I was again, working with my work truck, and heading up a VERY steep driveway and it went from 1st to about 5th then it was like I was driving a truck built in 1967 with a 3 speed..dieseling up the hill, wouldn't shift out until you pound the pedal again...of course leading to such a hard shift like a loud CLUNK it knocked my cel phone mount off the dash.

OH, last thursday turning a mild left corner my drivers side rear tire is skipping and chirping because its like its locked in 4wd but it wasn't. Went down and turned the truck around, more chirping..and it hasn't done it again in the last 4 days.

Have had to do 2 emergency stops now and both times when I went to accelerate nope..nothing at all...stalled cold.

Its going into the dealer AGAIN tomorrow which I am certain I will be met with "Well they are just another kind of animal and you have to get used to it"

45 grand and I have a truck that is probably the worst driving vehicle I have ever owned. It currently has 7200kms on it. Pretty sure I paid for a TRUCK, not a gas sipping grocery getter.

Sincerely a very displeased client