Auto body repair & detailing: auto paint, grease remover, white paint

Question
Hi i have a two tone truck. upper white lower red i want to paint the whole truck white can i paint white paint over the red with out doing any thing other then wet sanding

Answer
 Bill,short answer,yes .now the if's: If factory original paint is the red lower  all that is necessary is to clean with a good wax and grease remover first , two steps , first you need two clean rags  one to put cleaner on surface ,second ,while still wet use second rag to remove solvent and make dry, turning rag to clean side often .you will change second rag  several times  this is the step that removes the contamination from the surface. Next, sanding,wet is not necessary, you just want to sand,dry also works.Use a 400-500 grit paper to make the surface dull and smooth .Featheredge any breaks in the old finish to blend into surrounding area.If you cut thought to bare metal you will have to primer the spots.  If not original finish [repainted ]i recommend applying a coat of sealer before putting on the color. review ,1 clean, 2 sand , 3 paint. Have fun  Hope This Helps . Bill Tuma.