2018 GMC Savana

The Office of Defects Investigation (ODI) opened this Preliminary Evaluation (PE) after receiving one Vehicle Owner Questionnaire (VOQ) complaint related to four school buses built on General Motors (GM) van chassis. The VOQ alleged transmission failure resulting in a loss of all forward gear. In ODI's pre-investigative discussions with GM, ODI learned that valve body separator plates had been machined out of tolerance during production periods between October 2016 to April 2017 and February 2021 to April 2021. This out of tolerance machining may create excessive wear to the valve body check balls, possibly resulting in an inability to engage drive or reverse. The potential loss of drivability only begins when shifting from a park or neutral transmission selection and does not occur during a functional drive cycle. The average failure mileage of vehicles which experienced this condition is within warranty and related claims or complaints did not include any accidents, injuries, or fatalities. After discussions with GM, Technical Service Bulletin (TSB) 23-NA-142 (NHTSA ID number 10243753) was released in September 2023. This technical service bulletin provides a procedure for technicians to replace the forward check ball and separator plate if found to be the cause of a customer's concern. During the course of the investigation, GM also released a Customer Satisfaction Program (CSP) N232428780 (NHTSA ID 10253316) in February 2024, to notify school bus and ambulance fleets of the concern and to proactively mitigate the risk in these essential-operation vehicles. Recently, ODI 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 complaints since the opening of this investigation. Based on the available information, including GM's TSB and CSP, this PE is closed. The closing of this investigation does not constitute a finding by NHTSA that a safety-related defect does not exist. The Agency reserves the right to take additional action if warranted by future circumstances. To review the ODI report cited in the Closing Resume ODI Report Identification Numbers document, go to NHTSA.gov.

The contact owns a 2018 GMC Savana. The contact stated that while stopped at a traffic light, the vehicle stalled. The oil pressure light was illuminated. After several attempts, the vehicle failed to restart. The Police Department was called, and the Officer helped to push the vehicle out of the roadway. A police report was not filed. The vehicle was towed to the local dealer where it was diagnosed that the engine had failed and needed to be replaced. The battery was replaced, but the vehicle failed to restart. The vehicle was towed back to the residence and was not repaired. The vehicle was then towed to an independent mechanic, where it was diagnosed that the engine had failed and needed to be replaced. The repair was pending. The manufacturer was not notified of the failure. The failure mileage was 72,634.

NHTSA ID

11647360

Incident

Jan 21, 2025

Mileage

72,634 mi

MY 2018 VAN IS AN EXPLORER CONVERSION WITH 13000 MILES ON IT. IT WAS TAKEN TO GMC FOR REPAIRS FOR WHAT THE TECH IS CALLING A "DEATH WOBBLE". BASICALLY THE VAN AT UNPREDICTED TIMES GETS INTO A ROUGH SHAKING IN THE FRONT END THAT FORCES YOU TO STOP. THIS HAPPENED WHILE BRAKING GOING DOWN STEEP GRADES (5%+), ALSO TURNING ONTO A SLOPED ROAD AND AGAIN JUST TRAVELING ON A HILLY ROAD WITHOUT AND USE OF BRAKES. DEALER FOUND THAT 3 OF THE 4 RIMS WHICH WERE INSTALLED BY EXPLORER CONVERSION VANS ARE WARPED OR BENT. THE TIRE SIZE INSTALLED IS 20" WHICH IS DIFFERENT THAN THE STOCK SIZE OF 16". THE CURRENT TIRES ARE PIRELLI SCORPION VERDE 265/50/R20. THE VAN HAS ONLY BEEN DRIVEN ON STANDARD ROAD AND NEVER COLLIDED WITH OR RAN OVER ANY OBJECT IN THE ROAD. UNKNOWN AT THIS TIME IF REPLACING THE WHEELS WILL FIX THE ISSUE DUE TO ISSUES OBTAINING REPLACEMENTS. BIGGER CONCERN IS 3 OUT OF 4 WHEELS FAILING UNDER NORMAL ROAD CONDITIONS AND USE.

NHTSA ID

11376767

Incident

Nov 21, 2020

Mileage

13,000 mi

AFTER WAITING MY TURN TO PAY A TOLL ON THE OHIO TURNPIKE EXIT IN TOLEDO, THE VAN DID NOT STOP WHEN I APPLIED THE BRAKES AND I RAN INTO THE BACK OF THE CAR AHEAD OF ME. MY VAN BRAKES HAD BEEN WORKING AS WE EASED UP TO THE TOLL BOTH WITH ABOUT 6 CARS AHEAD OF ME. I HAD MY FOOT ON THE BRAKES THE WHOLE TIME. WHEN I WAS SECOND ON LINE, I EASED UP ON THE BRAKES. BUT, THE VAN WOULD NOT STOP EVEN THOUGH I STOMPED ON THE BRAKES TWICE VERY HARD, IT STIL WOULD NOT STOP.

NHTSA ID

11172369

Incident

Dec 30, 2018

Mileage

8,000 mi

PI to help diagnose A/C concern

This preliminary information communicates information about how to determine if a wheel and tires size change is available.

This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.

This Preliminary information communicates the steps on how to save a GDS2 Session Log and upload to a Technical Assistance Case in CX Connect.

This PI Communications information on an alternative product dealers can use to perform 19-NA-255: Wax Coating on Frame Peeling, Metal Shows Corrosion/Rusting due to issue with getting product from current supplier listed in the bulletin.

This PI communicates the proper part numbers for transmission connectors and internal harness to prevent confusion when ordering