GM Water Pump Drive Shaft Coupling

The water pump drive shaft coupling connects the cam-driven water pump drive to the water pump on L99, LT1, and LT4 engines. This genuine GM replacement is a good replacement for an original coupling that is worn, damaged, corroded, or otherwise questionable.

Because proper fit and function are important in this application, we recommend inspecting the coupling whenever the water pump is removed or replaced. O-rings should also be replaced during service. Worn or damaged O-rings can allow moisture and debris into this area, leading to corrosion of the coupling and splines and making future removal or installation more difficult.

Why we use the GM coupling: We’ve tested several lower-cost aftermarket equivalents sold online in an effort to find a more affordable option for our customers. Unfortunately, the versions we tested had fitment issues, with some fitting poorly and others not fitting properly at all. For that reason, we continue to use the genuine GM 10128334 coupling.