My buddy I do some work for has 2 1460's, one an '80 model, the other an '83. Older machine has so far broken 2 final drives the past 3 years, and the newer machine broke one this year. No bin toppers, 30.5-32's on both drives, 6 row corn heads, 17.5 and 20' grain heads, and relatively flat ground. Is this a problem on these particular machines? Gettin' kinda 'spensive changing these things out. And crunches up the sheet metal. Any thoughts appreciated.