Front end "clunking"

I have a 1997 Mercury Mountaineer with almost 118,000 miles. It is automatic with the 5.0 V8 engine. On a trip it began "clunking" on takeoff from a stop. This increased in frequency. We took it in to a shop and were told it was a part in the suspension that had to do with the all wheel drive. We were told that it would not hurt to drive it like that and was safe to drive back home where we could probably have the repair done at a more reasonable price. A mechanic at home removed the front drive shaft and said he would get a used one to replace it. We were told it was fine to drive as it was, only it would be 2 wheel drive instead of all wheel drive (this was confirmed by 2 other shops). He never came through with the needed parts. We just bought a new drive shaft to replace the one he removed, and the "clunking" immediately returned. What now??