trans question having trouble

[importedaze300]

recently bought a 99 350 driving the truck shifts fine and smooth no slipping but at idle with no load and have a rattling sound but when the truck is giving the throttle the sound goes away any ideas i am lost the truck has 146000 miles on it and 2wd

[jesilvas]

Probably the TC rattling. Some do it louder than others.

[importedaze300]

so is it something to worry about this momment i do plan on doing some light mods just night right now but i do wanna than you for your time

[JSchuricht]

Could also be the flexplate. I had one turn itself into a donut, initial symptom was the truck rattling at idle like it was about to fall apart.

[importedaze300]

what did you do to fix it just replace the flex plate or did you do a who tranny swap with new flex plate again yalls help is appreciated

[importedaze300]

so i took the truck to a friend and he says it is my tc he said i replace it and the sound will go away but i would like some input on upgraded or other tc that can be put in it again yalls time is greatly appriciated