Transposed a couple of characters, I believe; should be
MZCG, not
MCZG.Regardless, that's a K4 version, the last/best of the HRT216TDA models. FYI, the 'K4' is a version code Honda uses to note models with running changes, as Honda mowers don't have model years.
The TDA models were built with a non-serviceable transmission; if it tests bad, there are no service parts available, and the transmission would need to replaced as a unit; Google Honda Part Number
20001-VG4-H01 (MSRP $109.97). Not a difficult job to do
Did you buy it new or used? My records show it was never registered with Honda, and it would be a good idea to do that, in the unlikely event Honda should need to contact you regarding any Safety Recalls or Update Campgains. Drop me a PM with your full name and mailing address, and I'll get the database updated to show you as the current owner. FYI, that unit was built at Honda's plant in Swepsonville, NC, on or about 5/10/2007 to Home Depot in Commerce, MI. After that, the trail goes cold. Oh, and with a mailing address, I can at least send you a few Honda goodies!
Parts: Honda has a nice online parts-look-up guide; this is just a reference source, and does NOT sell parts. Good for looking up part numbers. Once you have the number(s), Google them to find a dealer selling that number online.
Linky here:
[url]http://peparts.honda.com/powerequipment#/browse/lm/hrr/hrr216/HRR216K4-TDA[/URL]
Many big dealers have similar look-up sites, that do provide retail sales; example linky:
[url]http://www.boats.net/parts/search/Honda/Lawn%20Mower/0/HRR216K4%20TDA/parts.html[/URL]
Owner's Manual: Free digital download direct from Honda:
Linky here: [url]http://cdn.powerequipment.honda.com/pe/pdf/manuals/31VL0U20.pdf[/URL]
Shop Manual: Honda sells paper copies of shop manuals online, direct from eBay or Amazon (free shipping). FYI, Honda does not distrbute or sell digital copies of shop manuals to consumers. Linkies:
HRT216K4TDA Shop Manual on eBay
HRT216K4TDA Shop Manual on Amazon