Saturn Astra transmission not shifting into 4th gear, TCM replacement needed on Saturn Astra

Some Saturn Astra owners report experiencing issues with their transmission not shifting into 4th gear, which may indicate a malfunctioning Transmission Control Module (TCM) that requires replacement. These owners have noted problems such as gear slippage, erratic shifting, and transmission stalls, which can significantly impact vehicle performance and safety. Signs of a bad TCM include inconsistent gear shifting patterns, and if the TCM fails, symptoms like being stuck in gear, a slipping transmission, or stalling during shifting may occur, often accompanied by warning lights such as the Check Engine Light or Transmission Warning Light. To resolve TCM-related issues, some owners find it necessary to replace the faulty shift solenoid or the TCM itself, as these components are crucial for proper gear shifting. The TCM is typically located on the back cover of the transmission case, near the Engine Control Unit (ECU).