Is my D44 broke?

Got an 87' 4.0, auto tranny with factory D44 rear. Every time the rear end is under load, such as conqueoring a steep hill, I get a loud ticking sound. The ticking "ticks" at every tire revolution. If the rear tire spins four time, I get four ticks. So I know its the rear end. Its not the u-joints. They would tick all the time. Does this mean the "clutch packs" need to be replaced?

I also changed the fluid with additive and no helpy. Any thoughts... Thanks.

sounds like you need to pop the cover and look in there. see if the teeth look like theyve been machining themselves or if you have a LS do whatever somebody who posts on here tells you what to do about that.