How many miles does it have, and do you have maintenance records? I have an ‘05 excursion with the same engine and transmission. They’ll last a good long while with proper maintenance. Read up on the engine, and issues it could have. In a nutshell, from what I researched when I got mine, they used silica based coolant, and if not changed as recommended it could break down and plug the oil cooler, thereby starving the egr cooler, causing it to overheat and break. Coolant would then get in the intake and blow the head gasket. As far as the transmission, if it’s like mine, it takes motorcraft SP fluid. Every 30k miles take the plug out and drain what’s in the pan, change the little secondary filter, top off with 8 quarts of fluid, and keep driving it.