Repair history ? How many working hours and what major repairs have you done?

<!–more–>I have 1660 hours on my 2001 Jinma(FarmPro) 254 with front loader . I use it at least once a week.

within 200 hours I had to replace a leaking into water jacket head gasket and found a damaged  guide/indexing ring  to index the head to the block during that repair. Obviously bad quality control during factory assembly.I never retorqued  the head since that head repair.

at about 700 hours I had to replace a slipping clutch although I never checked the clutch wear clearances until that point and may have exacerbated the problem.

at 800 hours I modified the front drive by removing  the balls in the front driveshaft and replacing them with 3/8” long case hardened dowels for flawless shifting

At 1200 hours I had to rebuild the front wheel drive. For that entire 1200 hours my tractor was engaged in 4 wheel drive and always maintained gear lubricant.
I suspect my front wheel planetary gear wore because a brass concave washer that would have protected that case hardened gear from eroding into its cast iron seat was never installed at the factory. It’s twin opposite in the same gear housing had a brass concave washer and those components were pristine after 1200 constant hours. I never found any brass shavings to indicate that brass washer was ever there.

Other than really minor repairs that is my tractors major repair history.
I would love to hear other members documented  repair timelines.