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2019 Transmission issue


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Feb 18, 2023
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Charleston, SC
Okay guys I need your help.

Got a 2019 Custom Trail boss with a transmission issue. When it’s warming up (even after letting it run for 5-10 minutes) if I take off from a dead stop or try to accelerate from a rolling stop it’s slips to neutral (not all the time. I’d say 4-6 times a month). It only happens when the engine/transmission are getting up to temp (once up to temp it drives great). I’ve taken it to AMMCO Transmissions and they confirmed the fluid level was correct and dropped the pan and told me everything looks great. Technician said “this is stumping me” and he thinks it’s internal but can’t know for sure unless they completely tear it down. Any idea what this could be? Greatly appreciate any help.
I’ve heard the 8spd trans has torque converter issues which could be the cause of your problem.
Change the fluid out and make sure you put in the blue label Mobil 1 Synthetic LV ATF HP fluid. In late 2019 or early 2020, GM swapped to the new transmission fluid and that corrected A LOT of issues with the 8 speed transmissions(clunking, hard shifting, stutter, shutter, etc.). Something about water getting into the fluid if I remember correctly, but being a 2019 you might still have the original fluid in your transmission that is not the re-spec'd fluid that GM required all the units to be switched over to.

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