I have a 2005 ford f-350 6.0 engine.I replaced a alternator, and after 2 minutes of running, the alternator got so hot to the point it burns the alternator.

What do you mean by it "burns the alternator?" Do you mean it just gets real hot?

Remanufactured alternators leave a lot to be desired. Most remanufacturers don't replace the bearings or the voltage regulator/brush holder assembly. They do a good job, however, of getting them "clean and shiny." I would exchange that alternator for another. There may be a problem with the voltage regulator or stator/rotor windings. It's always best, however, to begin by removing and fully charging both batteries. You want to, first, rule out a fundamental problem with the batteries. Most auto parts stores will do this for free.

Wen you start truck after 2 minutes alternator get so hot you can't tuch the alternator .I put new alternator not remanufactured and same problem.I test the batteris and test is OK.I don't now what is happening,new belt.

Remove the batteries and place them on a charger. The ammeter should eventually cut back to between 1 to 2 amps. If it doesn't, there's a problem with the battery.

Also, clean both ends of the "B" cable, going from the alternator to the under hood fuse box and then to the battery. Check the "Mega Fuse" at the end of the under hood fuse box. Ensure the battery cables are in good shape and clean.

Beside the heat, does everything work fine? There's always going to be heat associated with alternators--it's a byproduct of the process. There may be nothing really wrong.