Have a Kenmore (relabled whirlpool cabrio) washer with a failed drain pump. The impellar to rotor mount had failed completely (Shattered pieces). Installed new pump and went through full inspection and diagnostics. Found a F32 code (long drain time) - no surprise there.

During the inspection of post repair, found the pump was successfully draining the washer - and then kept running, running etc. Had to recalibrate the level indicator which reduced the run time to as expected.

However, the extended run time showed the pump hammering/slamming. The pump empties the tub, then loses prime (as expected). The column of water in the drain hose then falls into the tub, and the pump reprimes. The reprime essentially causes the impellor to hit the water. It's this constant hammer that eventually caused the impellar mount to rotor to fail.

Also noticed that during the drain/spin cycles, the pump will drain down (as above) and then shut off while the spin starts. The pump will come on periodically during the spin. This would be used to collect the water that was spun out. But once again, creating the hammering when the tub is emptied. And, if you are running a small load than spins out quickly - it results in more hammering - and faster pump failure.

The washer does not have a check valve. I'm thinking a check valve would allow the pump to loose prime and stay in freespin until shut off - extending the life of the pump.

Anyone ever install aftermarket check valve on these machines and did it achieve the above result? model/spec of valve would be helpful. Thx