I had a 95 wagon 5 speed with the exact same thing. It is without doubt the viscous coupler. It cost me $775 to have it replaced at the dealer. The tranny worked like a champ after the repair and as long as you keep the tires the same size and the tire pressure even I think it should last the life of the car. One more thing, always have it towed on a flatbed, and if you are towing it frequently you might want to consider getting rid of it...