When I first put it in drive it takes awhile to start moving. Then it acts like it's trying to find second until it shifts into third. Will changing the fluid and filter resolve this or should I look for another transmisson?

 

Its an automatic with the 4.2 btw.

 

Do a complete fluid change - drop the pan, change the filter, and drain the torque converter. Reuse the factory pan gasket unless it's damaged. You are gonna need 14 quarts of fluid, not particularly cheap, but probably worth a try. Use only Mercon V, not universal fluid.