I feel your pain!! I purchased a Lawn Chief lawn tractor at True Value hardware in 1993. Fantastic 46" lawn mower with a 16HP Briggs & Stratton Vanguard engine with a frame built by Power Equipment Company(builds several brand's backhoes and other heavy duty equipment). Several years later Ace Hardware bought out True Value and discontinued ALL of the "True Value products"(even the B & S engine had a label that said "designed and built for True Value"). Luckily, I found a local(mom & pop) hardware store that had a really good parts department and any time I needed any part(like idler pulleys, belts, blades, engine filters, etc.) they had a distributor that bought out all of the "True Value OEM parts" and even the belts I ordered over the years had "True Value" stamped on them. This little mower never missed a beat for 13 years with minor repairs and regular maintenance, but in 2006 it finally had a spindle bearing go out. By then, unfortunately, the local hardware store was no longer able to get those replacement parts for that 13-yr-old lawn tractor. Well......I couldn't complain about not gettin my money's worth now could I so I "parked it" and bought a 2006 54" Craftsman lawn tractor with a 24hp B & S Intek engine........even though the "tractor" was very nice(built by Husqvarna for Sears), the Intek engine didn't hold a candle(even "power/torque" wise) to that old 16hp Vanguard. A year later(2007), my father-in-law ran across a replacement spindle(new) online that was a match for the old Lawn Chief and my son had just gotten married and bought a home, so we repaired the Lawn Chief and it fired right up and ran like the day I bought it which made my son very happy!! After 6 years the B & S in my Craftsman was pretty well shot so I bought my new Gravely ZTR and gave the Craftsman to my son. Believe it or not he was STILL using that old Lawn Chief(now 19 years old) but the deck was rusting out and falling apart. That ole 16hp Vanguard STILL didn't use a drop of oil between seasonal oil changes.
Nice story, huh, but back to your dilemma......I learned this go-around(especialy when it comes to ZTR mowers)......NEVER buy one from a big box retailer(like Lowes, Home Depot, TSC, etc.) and I'm sure you can vouch for and justify why it's a bad idea. Users on the forum don't understand why I give that advice.....but for sure you understand.....right???? I'm really sorry to hear about your problem and I wish i had a solution for you. Don't shoot the messenger......but if the Dixon dealer can't help you I think you better consider buying a new ZTR(BTW, since you bought that Dixon ZTR, Dixon was bought out by Husqvarna and that doesn't help any either). Wish I had better news and hope maybe someone else has another recommendation:0(