Help!!1 overheating problem

[ocbaud]

the truck is still over heating.

its been doing this since i put in the new gears/posi.

when it was sitting and i put the gears in, i also changed the tstat and the fan sender.

the old 180tstat was stuck open and i put in a 200on/185off fan sender to replace the 180on/165??off

the truck would still over heat real bad, it would peg the guage all the way to 260 and stay there for a little while then go back down to normal temp.it did it about 5 times on the highway in a span of about 30 minutes. it doesnt matter if my heater is on or off.

i changed the tstat again with a different 180 unit and it is still doing it.
i also recently changed the heater hoses and it didnt help at all.

my dad noticed that my water pump doesnt sound really smooth like it should. could something wrong with the water pump cause it to overheat and act like that?

the radiator cap is the same one that was on the truck when i got it in 01', could that be a cause also??

i'm not loosing any coolant at all but when it does over heat i can smell coolant from the vents and stuff. i also ran the engine with the cap off the radiator to get most of the air out and filled it back up and its stayed full since.

i have no clue what to do next. i never had this problem before.