Yesterday was the first problem with my Totos now in use for 7 years. The chain lift pulled out of the flapper. No easy fix for the failure. Some sellers ask almost $25 for the flapper. 3" flush valve. Korky, Lavelle and Fluidmaster make flappers claimed to work on the Toto. After looking carefully, the Fluidmaster #5403 was my choice. Priced a little under $11 (plus tax) at Lowes. Works perfectly. Ingenious adjustments to fit different toilets. I believe that it will be more durable than the original.