I had a squeaking chirping noise coming from the driveshaft of my 2001 Tacoma. Took it to the dealer but they could not pinpoint the noise. I just greased the zerk fittings. Noise went away and there do not seem to be any ill effects. Cost about $18 total for the grease gun and the Mobil 1. Might be worth trying first. I'm pretty sure my dealer never greased the joints based on the way they looked. Good luck.
http://www.4x4wire.com/toyota/mainte...tml#driveshaft