New Holland MT40339977 is the fuel tank Clinton Tractor supplies for this application. It is listed as fitting 5 New Holland models.
What MT40339977 fits
Fits: New Holland WORKMASTER-25, New Holland WORKMASTER-33, New Holland WORKMASTER-35, New Holland WORKMASTER-37, New Holland WORKMASTER-40. Commonly ordered for the WORKMASTER-33, WORKMASTER-25, WORKMASTER-35. If your machine isn't listed, check the serial number before ordering.
Which numbers it replaces
MT40339977 replaces MT40229423. If your parts manual or the old box shows any of those numbers, this is the correct current replacement — no fitment change.