I didn’t know anything about the problems with the def system on these tractors when I bought my 2015 with 100 hrs, I have had 0 problems with mine, whether it’s 30 below 0 or 80 degrees, the last week I’ve been torturing this tractor, pulling monster rocks out of the ground, one rock has to be a ton plus and I dead dragged it about 1/4 mile, sum of which was uphill in wet and soft grass/dirt, low range, diff locked, 4 wheel, pedal through the floor, it just kept pulling , I have had no regrets.