According to Tractor Data, the TT75A production started in '07. There's no data there on serial numbers, so I'd reckon you've got a first year of manufacture rig.
1993 NH 2120 (the best), 1974 MF 135 (sold, but solid), 1947 Farmall A (bought, sold, bought back, sold again), 1956 MH50 lbt (sold, in 1980, darn it)
Strange question, you said it was your tractor? Front traction tires, 4wd shift lever, front diff not straight axle, front driveshaft, geared front hubs. Must be you're askin something else I don't get.
Jim
/ Any idea where I can find out the Model year of my TT75A?