Converting a RWD 21" to "Push-mode"

I've been offered an older Snapper RWD 21" mower which I've been told has engine (4.0) and transmission problems. It's one of the ones with the raised "SNAPPER" lettering in the cast iron deck.

I've never been a fan of self-propelled lawn mowers. Wondering if anyone has successfully removed the transmission from their Snapper of this era (80's?) who can offer any feedback.