Kohler Rialto flush gasket issue

I'm trying to replace the flush valve gasket in a Kohler Rialto toilet. I was able to get the old gasket off relatively easy.But I'm having a hard time turning the plastic piece (not sure what to call it-flapper assembly/flush valve?) with the new gasket.I can't get any leverage and I don't want to break it using channel lock pliers.It only needs about an eighth turn but I'm not getting anywhere.Any tips would be appreciated.

Push it down while trying to turn it and see if that helps.

Thanks for your response.That was a suggestion Kohler support provided and I had tried that without success.I just couldn't get a good enough grip to turn it.I did find a solution however.I applied a pure silicon lubricant to the gasket side that that touches the porcelain, the three plastic teeth and the part of the flange that the teeth slide over.I was able to turn it relatively easy.