Loud thud when getting off throttle?

Hey Reddit!

I have a 2000 4Runner Limited with about 218k miles and have noticed something strange after driving it today. It occurred when I accelerated to about 55-60mph and then let off the gas. When I did it sounded like a loud, semi-deep thud. It sounded to be coming from the transmission, almost like the tourqe converter not wanting to let go. It had done it before but few and far between. Another thing is acceleration is not affected and nothing has changed in terms of driving, or other unusual sounds like something is getting damaged.

Any help? Thanks!