2000 Other Holden Models Banging noise

When I have weight in the back of my 2000 VX Commodore a loud knocking noise comes from the rear right hand wheel. If I ease up on the excelerator the knocking stops and if I excelerate again the knocking sound starts again. I replaced the shocks thinking that may be the cause but it was'nt. Im lost as to the cause. I cant even afford a mechanic due not working as my partner gave birth to our baby boy 15 weeks early so I spend every possible moment at the hospital. Therefore any diagnosis you may have and any possible remedy to this knocking sound would be much appreciated. Hopefully I will be able to fix it myself. For any further information feel free to ask. Thanks, Richie.