Hold onto your cash! Use the "other guy's dough"!
IMO, if the vehicle is running good, keep it. Gradually make your mods, over time. You'll feel better about your truck and won't be tempted to buy "new".
Your probably at the end of your loan so paying it off right now is not going to save you that much, unless you plan on cancelling your full coverage, insurance. If you eventually get the urge and just have to have another truck, sell yours first, then buy a used 1 or 2 year old american truck, from a private owner. You'll save big, on the price and depreciation. If you can get a good interest rate on the next truck, get it, if you can't get a good interest rate, then pay cash That's not how I did it when I was young, but that's what I "should've" done!