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Reply To: 2016 Sierra 8-Spd Issue

#495975
swebber99
Participant

Hi all – Here’s an update on my experience dealing with GM and the dealer with “the clunk” issue on my 2017 Sierra SLT.
Ive been dealing with a GM executive office person who is assigned to you when you contact them about issues. Long story short they were helpful in pressuring the dealer to do another ride test on my truck. I had done a ride test with them before, but as many have experienced, the vehicle decided not to have problems during the test, so they claimed there was nothing wrong. (Note – 5 months earlier they had experienced a problem and did a refresh on the tranny which initially worked for about 1000 miles. After a few thousand miles more of experience the problem again the dealer apparently got tired of dealing with me and decided to forget they had seen the issue AND forget that they had told me they had seen the issue with other customers.) Hence the need to get GM to pressure them to look at the problem again. Fun.

NOTE: When you deal with GM directly, although helpful in managing the process, they will label this issue as a “Characteristic of the vehicle” and therefore ineligible for any kind of buyback. So now you know the obvious, widely reported defects in GM 8L90 and 8L45 transmission are actually built in “features” that you should be happy about after spend $60k! Professional Grade Baby!

So just had another ride test where the tech plugged in a computer and we went for a long drive. We did experience the “clunk” and the tech acknowledge the issue in general with other vehicles. He said that they had tried to get direction from GM regional techs on how to fix, but no help was forthcoming. We identified the main issue as a “learning problem” impacting deceleration from 3rd to 1st gear. The tech recommended I bring the truck back in and he will try to modify (relearn) the software shifting to remedy that, based on the ride data picked up during the test drive. Ill report back here with results.

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