transmission issues (5spd manual)

i have a 2008 prerunner 2.7, 5spd manual, 2wd. well, i had been getting alot of chatter from the transmission. it got real bad, to where you almost couldnt hear the engine running over it. i had 59,000 miles on it at the time and i knew the service manual called for a transmission fluid change at 60,000. well i took the liberty of doing it myself. well, a lot of cussing, a lot of oil everywhere, and a lot of headache, i finally got it done. much to my suprise, when i cranked it back up, there was no more chatter. i was amazed that i could actually hear my engine running. well now i have 62,000 on it and ive noticed that it chatters a little bit after a long drive and its kind of bad when the a/c compressor kicks on. i know some chatter is normal, but what makes the chattering and what can i do to fix it? also, why did it go away when i changed the oil?

another issue i have had is that i do not get very smooth shifts. i have had the truck this long and i find that you still have to be very particular and exact to drive the damn thing. ive read posts online where ppl have experienced the transmission completly locking itself up in neutral and then being able to shift it again after a few mins, but very sticky-ly. this has happened to me before at about 45,000. maybe i need to just change the entire clutch/pressure plate out? please help!

 

Put in Redline Heavy Shockproof transmission fluid. LINK --> http://www.redlineoil.com/product.aspx?pid=44&pcid=8

This oil made my friends problematic 6speed on his Nissan Sentra shift amazing...

The chatter is resonance from the aluminum tranny housing. I absolutely HATE aluminum, worst metal ever. Auto manufacturers worship aluminum, because its light weight & cheap, the downside is that aluminum is weak and resonates sound more. I bet the noise is not as bad when the engine is cold. That is because the tranny fluid is thick and dampens the sound better. When fluid gets warm it gets thin and doesn't dampen the sound as good, same thing when the fluid wears down with mileage.