I found that same clunking on my 87' when shifting from Park to Drive and chased it down to bad rear suspension bushings - Try this, put her on level ground, with saftey in mind, place it in neutral, get back up wheel chocks just in case with room to move wheel back and forth by hand, move yourself in the path of the vehicle (remember the chocks) rock the wheel by hand back and forth while checking the link bushings or have a buddy that trusts you with his or her life check, the kit is about $300 from Rovers north include the center bush (might as well) or have the dealer put it in for about a grand (yeah that's what I said too)
Good Luck