issue Transmissions Issues/Problems

BluByU14 · January 9, 2015

I have a similar story. I was stopped at a red light and I saw a car coming up behind me at a fast rate of speed. I accelerated slowly so I wouldn't get rear ended and NOTHING, then all of a sudden the truck jerked forward and I nearly hit the car in front of me. It jerked me so hard that I wasn't sure if the car behind me had hit me or not. I pulled over as soon as I could to check the back of my truck and saw I hadn't been hit. Damn this transmission.

Feeling the same thing with my 8-speed. Taking into dealer next week based on the recent Service Bulletin for harsh shifting in the 8-speeds..... I can deal with a minor clunk here and there but the jerking and banging is unacceptable.

TX14Z71 · January 9, 2015

Feeling the same thing with my 8-speed. Taking into dealer next week based on the recent Service Bulletin for harsh shifting in the 8-speeds..... I can deal with a minor clunk here and there but the jerking and banging is unacceptable.

I dropped my truck off today for transmission, onstar, and I asked them to check accelerator pedal. I'll let you know what happens.

TX14Z71 · January 9, 2015

Ok, got my truck back.

1) they acknowledged the hard shifting and did the work on the service bulletin. It's been shifting way better so far.

2) They diagnosed the onstar problem and said the onstar module was bad and ordered it. 3) They checked the accelerator and said it was within specs.

No invoice yet until they complete the order when the module arrives. I'll post it then.

mjj · January 22, 2015

I asked the service manager at the dealership I bought mine from about the erratic behavior of the transmission and was told it's an adaptive transmission and can take about 10,000 miles to learn your driving style. I wasn't sure if I should have started laughing or take him seriously. But I ended up taking the advise of some others on here and tried the Diablo tune on it with the firm shift option for the TCM and torque management off. I think it makes a world of difference. After several weeks I put it back to stock and was blown away by how oddly the stock TCM tune acts. Its like it gets confused and doesn't know what to do.

f8l vnm · January 22, 2015

They tried to engineer gas savings but instead engineered the worst driving truck ever. Confusion is a good word.

triguy450 · February 27, 2015

I did read the lengthy checklist that ujtruck posted.

99 K3500, crew cab, diesel dually. I seized the motor 2 years ago because the clip holding the oil cooler line into the motor broke, sending all oil out of the engine. the truck sat for 2 years until I could gather the money to find a new motor and install it.

I did replace the rod that sticks out of the transmission and secures thru the neutral safety switch. I replaced the fluid and the filter while I was at it. I did put synthetic fluid in it because the auto parts store did not have non synthetic fluid available. My plan was to drive it to a transmission repair station, flush the entire system and replace the fluid again. 5 miles away.

I started the engine this week. After a thorough warm up, I put it into drive and the transmission made a lot of noise. I went thru all the gears. 1 & 2 and neutral were quiet. 3, drive and reverse were noisy. I placed it back in park, the noise continued until I turned off the engine. I restarted the engine and the noise went away. I put the transmission back into drive and tried to move the truck. It wouldn't move. I tried reverse, it did not move. I tried the remaining gears, it would not move.

Anyone have any theories which direction to take next? I am considering a flat bed to the transmission place to have it looked at.

Thank you

Ed

pm26 · February 28, 2015

I asked the service manager at the dealership I bought mine from about the erratic behavior of the transmission and was told it's an adaptive transmission and can take about 10,000 miles to learn your driving style. I wasn't sure if I should have started laughing or take him seriously. But I ended up taking the advise of some others on here and tried the Diablo tune on it with the firm shift option for the TCM and torque management off. I think it makes a world of difference. After several weeks I put it back to stock and was blown away by how oddly the stock TCM tune acts. Its like it gets confused and doesn't know what to do.

And by the time it "learns" your driving style it will most likely suffer serious internal damage from those harsh shifts and banging into gear. This is definitely the proverbial"blowing smoke up someone's ass".

An "adaptive transmission" would be expected to slightly alter its shift points based on driving habits. Not to start shifting harshly and then somehow smooth out the shifts. Transmission shfting controls need tuning here.

Gunner99 · March 7, 2015

Put me in the category of "clunk city". Can't say I get the superhard shifts you guys talk about, but when you back off in 2nd and 3rd, then re-accelerate, sometimes there is a pretty hard clunk, almost like a driveline slap. (In the old days you would think you had a bad u-joint).

Should I keep hoping it "learns" how to drive with me? 2100 miles.

This describes exactly how mine and many others shifting is. Also there is the clunk or hard click when you accelerate from a stop or go into reverse.

pm26 · March 8, 2015

I dropped my truck off today for transmission, onstar, and I asked them to check accelerator pedal. I'll let you know what happens.

I am surprised that they did not just give you the NORMAL treatment.

55Cameo · March 10, 2015

So I finally found a guy at the dealer who (I thought) knew what I was talking about, he even said he had talked to a tech (there) that knew a tune fix (reset codes?). So I scheduled an appointment, left the truck. Guess what....they all got amnesia! They said a tech drove the truck and could not get it to "perform anything but normal functions". He drove it two miles.......

I unloaded on the service manager guy pretty good, (maintaining proper decorum of course). I finally got him to admit that maybe there is an issue with this transmission and that "I should bring it by sometime and take him for a ride."

I travel a lot for work and my weekends are scarce where I have time to go take this yahoo "for a ride". My point with him was, so if you hear it go "clunk" or get get whiplash from a hard shift, then what? To me its obvious these guys don't have a fix for these problems.

Anybody know of a transmission that's actually been "fixed"? Oh yea,this guy also said Service Bulletin #PIP5175B did not apply to my truck since it was not assembled in Mexico. I don't get it...I just don't get it.

I told the guy I have 10 year old Dodge 3/4 ton work trucks that shift like a dream compared to this $50k nightmare.

Not sure what to do.

Again: Anybody got one fixed right yet?

f8l vnm · March 10, 2015

Allot of us are in this same damn nightmare. Truly sad how GM is turning a deaf ear to this. I always wonder if they think people with gripes are just lying to them ? How else can you explain the " Its normal" BS.

" Dealer says its normal., and its still learning "

Really?????????????????

Newell33 · March 10, 2015

Allot of us are in this same damn nightmare. Truly sad how GM is turning a deaf ear to this. I always wonder if they think people with gripes are just lying to them ? How else can you explain the " Its normal" BS.

" Dealer says its normal., and its still learning "

Really?????????????????

I'd like to trade my truck back in for one that took the higher learning classes, not the special needs classes. Mine is at 10,500 miles, and it's still as dumb as it was when it was brand new!

CounterMeasure · March 10, 2015

A good transmission guy I trust recently told me not really believe the "its still learning" line, because unless you drive all over, it never comes out of learning mode. For example, there are shift parameters for high altitude versus sea level. Supposedly, the Tech2Win equipment can actually show which learn scenarios haven't happened yet. So if you live in the mountains, and then suddenly take it to the beach on a family vacation, it can act funny while its building sea level shift patterns.

Normally, I wouldn't be bothered by this, as my last truck had an adaptive transmission as well. However, you couldn't tell it was doing anything different. In my Denali, its a roll of the dice at which temperament I am going to get from the transmission when I put the key in it. I don't want to have to think about how the vehicle will act if I go on a family trip.