Food for thought, your seawaterpump and transom inlet housings are plastic

Rookie question:

If I add a T to the inlet hose (from the transom assembly to the bravo pump) between the TA and bravo pump to flush my motor, heat exchangers etc, instead of using muffs on the drive, I'm ok doing that, no problem with the drive or anything else upstream from the T that will no longer be getting water?

thanks