I was in a junkyard where someone was pulling a transmission out of a VX. the cross member (transmission rear support) was laying on the ground and was in perfect shape so I took it home with me. Mine was badly dented and when I pulled off mine and set them side by side mine was bowed up 2in in the middle where the transmission sits. I put on the undamaged cross member and that thud after braking then taking off was gone. Coincidence? Maybe. Can't explain why that helped, but now after 2+ years it hasn't done it since.