my starter ingagues but won't turn truck over thought it was the starter but replace it and still does the same thing.

Make sure starter engages and spins off of the truck also check battery and connections, check to make sure engine turns over. You should be able to grab harmonic pulley and turn engine to make sure it is free.

Check your battery make sure you have good clean connections , especially all your ground wires negative , Then using a multimeter or just a DC voltmeter check battery voltage should be between 12 to 14 V DC when the battery is standing unloaded across the positive and negative terminals. if the battery shows it has 12- 14 V engage the starter if the battery immediately drops in voltage when the ignition switch is engaged the battery is more than likely your problem it is not producing enough amperage to turn the engine over. A feecautions if you check the starter when the starter is unbolted from the block you may have enough amperage to turn over the starter however you still may have a bad battery because the starter has no load obviously without being connected to the engine. never underestimate the possibility that you have a defective new starter also. In my experience a lot of the times the problem lies within the battery connections or a ground that's not sufficiently tightened.

altinater check that out too check the connections the starter starter cylenoids