We have a 2008 F250 6.4 CC KR Job build 2 and we have been very happy. With a 3.73 rear end we see 16.5 mpg average (city / hwy) and 19-20 on long highway trips, all averaging 70 mph (empty). When we towed an 8K boat, we got around 12-14 towing at 60mph. I drive conservatively, so if you put your foot in it, you will feel it in your wallet.
Our truck is at 60K and we haven’t had any major issues, a few small problems. DPF sensor wires laying in a manifold, fuel water separator housing leak, rear camera replaced, trim pieces (double sided tape failing), and seat memory system that doesn’t want to hold the settings. I just put 4 new Michelins ($1650) and we are ready for another 60K.
I would highly, highly suggest you get oil and transmission fluid samples analyzed (
http://www.blackstone-labs.com/) . The analysis would be a great indicator of the engine and transmission health. Get them done early so if there are any metallic particles or other indicators that might suggest coolant leaks, trans clutch damage, fuel dilution, or other potential problems you can get them taken care or at least noted by the dealer or walk away from the deal if needed. I would do this if buying ANY USED DIESEL TRUCK, REGARDLESS OF BRAND. Diesel engines are great, but the maintenance is expensive ($250 oil changes) and thus people tend to skip maintenance. Additionally they are easy to modify for large power numbers and that can lead to future problems. Diesel engine repairs can be very expensive and quickly rise to tens of thousands of dollars. I am not trying to scare you, but take an opportunity to give yourself some insurance. I would also continue the practice during your ownership. The oil analysis will allow you to identify potential problems early, before they get expensive.
Good luck and congratulations on the purchase.
OJ