I say at that point you should keep in and buy something hybrid, you drive too many miles lol.. Unless you need a truck for all those miles, you could buy a prius and with the money saved on fuel after 3 years you could buy a truck cash...
Other than that I would say if it runs good, no issues, keep it and bank the rest.
My Dad has a dodge caravan and it is near that, it's a 2011, he drives for work. it is paid for, he can get about 6k trade in now and realistically in a year it will be 5k, so he might as well keep driving the hell out of it and bank all the monthly allowance so he can make up for the recent changes due to economic downturns causing him to actually pay for his vehicle at all when 5 years ago it was no cost to him for anything... and no raise in 8 years...