I’ve read thru the 6l80 threads but haven’t seen anything exactly like what I’m seeing with my 2009 Yukon Denali XL. The truck has just under 164k miles.
1. When cold and under light throttle or if I have to lift throttle slightly just before a 1-2 or 2-3 up shift, the transmission will shift with an audible clank. It doesn’t happen again after the first run through the gears. It doesn’t clunk on downshifts at all. Is this fixable, and does it need to be addressed?
2. I often get a flare on the 2-3 upshift. It used to be only when cold but can now happen any time under light throttle and can occur on the 3-4 sometimes. It doesn’t slip at any time and doesn’t flare under moderate or heavy throttle. The dealership says 2-3 flare is normal. They did a fluid/filter change and reset the shift adapts. It was better for a few days but went back to doing it. Maybe this is just regular old torque management weirdness.
I had a GM dealership check the trans and they said the fluid was dirty. This was a used truck and I checked the trans fluid myself a couple of times in the months before I took it in and the fluid was actually okay - not too dark or stinky and no burned smell. There is a powertrain warranty for the rest of 2023. I played along and did the fluid so I could show I had done maintenance to it for the sake of any future warranty claim. We have had it for 16 months and I plan to keep it another year at least and would like to be proactive if the trans is in the early stages of needing to be redone.
1. When cold and under light throttle or if I have to lift throttle slightly just before a 1-2 or 2-3 up shift, the transmission will shift with an audible clank. It doesn’t happen again after the first run through the gears. It doesn’t clunk on downshifts at all. Is this fixable, and does it need to be addressed?
2. I often get a flare on the 2-3 upshift. It used to be only when cold but can now happen any time under light throttle and can occur on the 3-4 sometimes. It doesn’t slip at any time and doesn’t flare under moderate or heavy throttle. The dealership says 2-3 flare is normal. They did a fluid/filter change and reset the shift adapts. It was better for a few days but went back to doing it. Maybe this is just regular old torque management weirdness.
I had a GM dealership check the trans and they said the fluid was dirty. This was a used truck and I checked the trans fluid myself a couple of times in the months before I took it in and the fluid was actually okay - not too dark or stinky and no burned smell. There is a powertrain warranty for the rest of 2023. I played along and did the fluid so I could show I had done maintenance to it for the sake of any future warranty claim. We have had it for 16 months and I plan to keep it another year at least and would like to be proactive if the trans is in the early stages of needing to be redone.
