The Nissan Path

I introduced myself yesterday or a couple days ago about buying a 1998 Pathfinder with 75,000 miles on it. I was able to test drive it today and when I would accelerate from a stopped position I could feel a slight slip and then a final engagement of the rear wheels. It almost felt like I was loosing traction or spinning the tires slightly. Would anyone have any idea what this could be.
Thanks for any info in advance!

Wife reported the same on our 2002 pathfinder - auto trans. Very slight slip feeling. Rarely happens but it does.

Anyone know of this and what the fix is?