In February 2024, we reported that GM had released a fix for a transmission control valve issue in the Chevy Express and GMC Savana vans. Now, the National Highway Traffic Safety Administration (NHTSA) has closed an investigation into the Express and Savana for transmission failure, having found no cases of crashes, injuries, or fatalities related to the transmission problems.
Customer Satisfaction Program N232428780 issued last February applied to Express and Savan models from the 2017-2021 model years. Affected units may have a condition where the transmission Control Valve Body Ball Check Valves can prematurely wear, which can cause them to become stuck or pass through the Control Valve Body Space Plate.
If this were to occur, the driver may not be able to shift from Park to Drive or Reverse once the affected vehicle begins operation. To remedy this, certified GM technicians are instructed to inspect affected units and replace the transmission Control Valve Body Spacer Plate package.
The NHTSA opened its investigation into these transmission problems back in September 2023. Its primary concern was with school buses and ambulances that use the Chevy Express/GMC Savana Cutaway models as their basis.
“Recently, ODI (Office of Defects Investigation) contacted multiple school bus fleets, verifying that there have not been any stranded buses mid-route from this condition. Additionally, ODI has not received any additional VOQ (Vehicle Owner Questionnaire) complaints since the opening of this investigation,” the NHTSA said in a statement. “Based on the available information, including GM’s TSB (Technical Service Bulletin) and CSP (Customer Satisfaction Program), this PE (Preliminary Evaluation) is closed.”
The specific transmission in question is GM’s 6L90 6-speed automatic. The 6L90 is considered a heavy-duty transmission, and it’s been used in conjunction with the 6.0L V8 L96 and 6.6L V8 L8T in GM vans. Chevy Express and GMC Savana models with the 4.3L V6 LV1 or 2.8L I4 LWN turbodiesel Duramax engine weren’t affected by the investigation.
Comments
I have a 2020 Express 2500 with the 4.3L engine and the transmission has slipped in the first shift of the day only. Chevrolet has not been able to fix it. It has been back to the dealer 6 times. I don’t know what to do because I don’t trust it and now I can’t sell it and the dealer won’t give me anything trade in for it because THEY cannot resell it. It only has 70k miles and I need a dependable van. Thank you.
My transmission has always slipped first of the day, i always let it warm up for a couple minutes, never slips then.
Victor, either your dealer does not know anything about the product he is selling or he did not pick up the phone and call GM and ask. Even the manual that came with the van warns about cold weather transmission actions. A 2020 with that low of miles is very easy to sell. Most of the ones I have seen have over 100,000 miles on the clock.
GM auto transmissions tend to slip sometimes changing to the next gear when it very cold and the engine isn’t warmed up. The first time I experienced this I thought something was wrong until I read that this was normal and goes away shortly after fully reaching full operating temperature. What bothers me is the TCM is making decisions that are best suited for the drivers to decide. GMs latest recall of the 2022 and 2023 TCM is a joke. With only 24 complaints out 79,000 vans is easily corrected by resetting the TCM.