88-90 Gm Th400 375 m40

The 88-90 GM TH400 375 M40 automatic transmission shift kit from B and M AUTOMOTIVE is designed for enthusiasts and professional mechanics looking to enhance the performance of 1988–1990 GM TH400-equipped vehicles. This shift kit addresses the common issues of lag and soft shifts in stock TH400 transmissions, providing improved response and control during spirited driving and hard launches.

By recalibrating transmission fluid pressure and shift valve timing, the kit reduces converter slip and increases shift firmness across all gears. It modifies the pressure regulator and shift valve assembly, allowing the transmission to hold gears longer under load before upshifting, which enhances off-the-line performance and mid-range torque feel. This precise hydraulic tuning maintains the TH400's durability while eliminating the delayed response typical of stock setups.

Ideal for those building street machines or restoring vintage Chevys, this shift kit transforms the driving experience without sacrificing reliability. Weighing only 0.88 lbs, its compact design allows for straightforward installation for mechanics familiar with TH400 service procedures.