Well… It worked. I’m not sure if they pretended like all they did was a recalibration, but they actually replaced the transmission or something, and they’re not allowed to tell me because of General Motors’ orders. It’s very possible that the private mechanic was just telling me what I wanted to hear to make me a happy customer. I’m not an expert with the inner workings of automobiles, so I may never know. But my truck’s transmission is buttery smooth now. It drives like the day I bought it. I feel like, after this, I think I might have even more questions than answers, but at this point, I’m just thankful that my truck doesn’t jerk backwards like it crashed into something every time I accelerate from low speeds.
Problem: One of the more common 8L transmission problems is excessively hard or abrupt gear changes.Solution: The TCM may need to be recalibrated with the latest control software. It could also be caused by one or more of the clutch fill times not being learned by the TCM. In which case, the Service Fast Learn (SFL) procedure will have to be performed. Should the problems persist, the valve body will need to be replaced.
While I was on my most recent California trip, I had my pickup truck dropped off at the dealership for some more warranty repairs. If you’ve been following this story for a while, you know that my GMC Canyon has a storied past of issues with the transmission, even though it has just barely over 12,000 miles on it. As a reminder, just under a year ago, I did an owner’s review where I listed off all the problems I had encountered during my half year of ownership, one of which was a lurching and jerking transmission. The worst part about this was that all the dealerships I brought it to said that the transmission was working as intended, and everything was in fantastic shape. AutoNation Buick GMC Henderson sent it back to me twice saying that my transmission had no problems, and when I asked a Cadillac dealership that was fixing my flat tire, they said they did an inspection and found nothing wrong either. Not long after my issues with AutoNation Buick GMC Henderson, I discovered that there’s actually a class-action lawsuit against General Motors for their 8-speed automatic transmission that’s currently in my GMC Canyon. After figuring this out, it all “made sense,” and it was clear why my truck was just being sent right back to me with the claim that everything is fine—General Motors was allegedly telling the dealerships to do exactly that. I enrolled as a contributor for the class action lawsuit and worked with a lawyer initially, but haven’t heard back with anything more. I did a bit of digging recently, and apparently the latest in the case is that General Motors filed a motion to dismiss the case. Eventually, the transmission lurches got so bad that I felt like I still had to keep trying and take it back to a dealership. Even if they wouldn’t fix it, I still needed to have all this logged in the vehicle’s history so if I do pursue legal action, I have plenty of evidence demonstrating that I attempted to get it fixed. Seeing as AutoNation Buick GMC Henderson’s technicians were wildly unhelpful and disconnected my dash cam, which made me suspicious of them, I decided to go with a different GMC dealership, AutoNation Buick GMC West Sahara. Now, I already wasn’t really a fan of AutoNation Buick GMC West Sahara, because I actually initially tried to purchase my vehicle from them, but my salesperson stopped responding to me, so I went and bought the vehicle from AutoNation Buick GMC Henderson instead. Regardless, I went online and set up an appointment with West Sahara, then followed up with a phone call to let them know that I would need a loaner vehicle while my truck was dropped off. Aaron said that he would call me back and let me know when a loaner would be available, but he didn’t call me back for a month. Literally a month later, I called them back and spoke with Aaron, asking him what was going on. Apparently, they had zero loaners come through for the past entire month. Now obviously, that could mean one of two things: either Aaron was lying and he just forgot to call me back, or they are actually literally so bad at fixing vehicles that they have been keeping people’s cars and trucks in the shop for over a month at a time, which in the latter case, I wouldn’t want them to be the ones fixing my truck anyway. At this point, I just wanted answers, so I went to a highly-rated private mechanic in southwest Las Vegas. I asked them to do an oil change, and while they had my truck, I also requested a multi-point comprehensive inspection. Within an hour or so, they had everything done and said that there was severe damage to the transmission, and that the problem had not been addressed for so long that the transmission had irreparable damage that would cost about US$8,000.00 to fix. Now at this point, I was a little conflicted as to how to feel. I was relieved that at least someone acknowledged I wasn’t going absolutely insane and that there was indeed a problem… but the repair cost that they quoted me was unusually high—higher than what I would estimate it would cost to replace my current transmission with a brand new one. So did that imply that the transmission had damaged other parts of my truck too? Regardless, the repair cost didn’t matter, because the private dealership refused to service my transmission. They said they would not make me pay several thousand dollars to fix a transmission that is still under warranty, and the service manager helped me schedule an appointment with another different dealership so they could actually look at my truck. I didn’t want to go through the hassle of coordinating and waiting for a loaner, but the timing was fortunate enough that I could drop it off before my two-week California trip, so that’s what I did. Fast forward to now, and I picked up my truck at Fairway Buick GMC. My service advisor was surprisingly competent and professional, and he realized that what he was about to tell me wasn’t something that I wanted to hear, but he said that the problem with my transmission wasn’t actually as severe as I may have thought. He is unsure why the private mechanic thought there was $8,000 worth of damage, but he said that the mechanics were able to fix the transmission’s shifting problems. According to the service report, my guess is that they took the steps covered by this service bulletin: