loud snap when shifting

so my 94 gt started making a loud snaping sound when i shift from 2 to 3rd and again fron 4th to 5th but not any other gears or when i downshift. any ideas? also a new rattling noise has started, im thinking my tranny to engine bolts are loose but i wanted input of other things to check for when i check those.

still cant figure it out

ok so everythings tight, i replaced mtr mnts, trannt mounts, rear control arm bushings, and cant figure it out. its an intermiteb problem like it doesnt haprn all the time an when it does make that noise its not realy under the same situations like full on throttle er whatever. im thinking maybe its just the shift boot or something external nocking around as my shift boot just hangs the base isnt attatched. well anyway ill let ya know what i find when i find it hopefully its gna help someone sometime down the track