had frontier 2006 in the shop for parts of 2 days, due to the "clang"

metallic clang sound is heard after car intially started, hot or warm and gears change
from 1st to 2nd, sound occurs very loud if engine has been off for 8 hours, less if
engine off just a few minutes

the service manager drove with me and heard the "clang" and wrote it up again but when
I picked up next day, he said he did not hear sound again

yet, when I pulled off their lot to street, there goes the "clang" again....

it only occurs once per engine start, no sounds when engine running and taking off
from a stop sign or traffic lights

suggested to them to check driveplate bolts but no solution found