Harwired range

[AZsparky]

I've run into a Dacor hardwired range that has a factory installed 4 wire 1/2" flex whip. The existing outlet has a 40 amp rated three wire feeder. The whip does not appear to be serviceable (accessible) without major parts being taken off. A new 4 wire circuit is not economically possible. It was hooked up with this configuration for three years before the client decided to add new kitchen cabinets. How to wire back up?

 

[iwire]

Neutral and EGC joined together to the neutral of the feed. It is code compliant for existing.