There is a special screw that holds the inlet valve on the back of the Kenmore elite front load washing machine. A phillips or regular screw drive doesn't fit and the edges are smooth and round. Help

Does it look like this? If so, this is a Torx screw, and drivers are available for them.
If I had to guess, I'd say it is a T15 screw.

Best of luck,
WallyH