when I make a quick excelleration there is a very loud bumping sound in the rear

Hello Eldermcd, Thank you for your question. This is most likely driveline related, either in the rear end, axles, or possibly driveshaft. It is of course difficult to say with any certainty what it could be without hearing the noise... I have even seen a vehicle before that made a similar noise, and it turned out the owner's friend had zip tied a bolt to the driveshaft as a prank! Is there any chance you could come see us so we can have a look for you?