vc tranmission problems

[counc]

hi guys new member long time holden lover here.

I own a vc commodore 5L v8 auto tranmission
Yesterday i was taking my son to school, and as i accelerated out of my street there was a loud clunk
Ive since check the following:
1) fluid levels
2) correct fluid
3) the adjust selector linkage

all are fine from what i can tell.
does anyone have any ideas what else i should look at before i rip her apart or even worse take her to the mechanic :bang:

cheers
Counc