Does the noise happen when you shift into Reserve then get hard on the accelerator?

 

I mean REVERSE

 

I know this wasn't on an xj, but I had a dodge spirit that made a thumping noise on acc, or when it had a load in the rear,etc.It was the bushings on the sway bar begin wore out that it wasn't holding it tight like it should allowing it to slam up and down, I don't know if this will help you out but it does sound similar and who knows maybe it will help. g/l

 

Checking the lug nuts and studs would be an easy (and free) start. I had similar symptoms years ago, it was lug nuts that were loosened for a 'joke'.

 

Dragging the dead body out from under my wag made my strange noise go away! And......so did changing my u joints lol but yours are good tho

 

i checked the lug nuts there fine there is no rear sway bar i pulled it off and it isnt when i put it in reverse it doesnt matter

 

actully i havent tried that yet

 

Have you tried Reverse yet??

 

If it does make the noise in reverse what does that mean? I will try it tomorrow

 

I have the same noise in my 88. It does it when I start out sometimes and always does it when i start out with the wheel all the way to the right. Mine turned out to be the exhaust pipe hitting the cross member. I don't know why but, I've decided to live with it considering I only start off with a hard right once a day.