Whirlpool leak repair help

[shaefins]

My dishwasher is leaking - confirmed it’s dripping from what I believe is the plastic housing the motor. Found out on another forum that it’s the gasket/grommet under the lower spray arm. Ordered a new one, pried the old one out and can’t get the new one in. Do I have to take the motor out (there’s a white plastic piece sticking up through where the gasket/grommet goes, that the lower spray arm screws onto) to get the grommet/gasket in? Any advice? Thanks.