2017-2019 Duramax L5P T87A Transmission Tuning Package Duramax LML Hard Parts Received within 31–45 calendar days:

Received within 31–45 calendar days: 50% refund — $750

Reliable signal emulation — mimics the factory sensor’s resistance range so the ECM reads a healthy coolant level even when the original sensor fails

Level 4: +100 HP

ensuring seamless access and instant updates

Level 0: Stock Output

2017-2019 Duramax L5P T87A Transmission Tuning Package Duramax LML Hard Parts Received within 31–45 calendar days:Whats Included Transmission Tuning Configuration Four (4) HPTuners Universal CreditsRequired for TCM unlocking and flashing. As of November 18, 2025, HP Tuners has officially released direct OBDII flashing support for the GM T87A Transmission Control Module (TCM), eliminating the need to remove, ship, or exchange of the TCM unlocking