My 1990 Geo Prizm with 158,000 miles suddenly started making an clunk-clunk-clunking noise only when it is in gear, running down the road. It did this after a momentary loss of power during which time it felt like it was in neutral. At first, when I accelerated, the engine revved, but no geared response, then it came back, but with the clunking noise. This noise does not occur during idle, only when running down the road in gear. I have had no other transmission problems. I did have th eCV axle joints replaced about 2 months before this happened. Also, maybe related, maybe not, I checked the fluids the other day and found some oil in my radiator reservoir. No water in oil. Car has never overheated since I have had it (2 years). Any ideas about clunking? Not sure if I want to fix it or not. Thanks.