To build the hydrogen engine, JCB started with the bottom half of the existing Dieselmax model. The sump and cylinder block are the same as the diesel-powered model, as is the cooling system.

See also: On test: JCB’s new TM420S pivot-steer telehandler ... The engine is the same 4.8-litre, four-cylinder Dieselmax used by larger TM models, albeit with slightly less zesty performance.