front drive shaft noise

[Ray Fischer]

I have a 91 4x4 Explorer XL automatic with shift on the fly. When I am in 4 wheel drive the front drive shaft makes a clunking noise every 10 to 15 seconds depending on the terrain. I first thought the noise was from the transfer case as it sounds like a chain jumping but have since discovered that it is coming from the front drive line. Any ideas as to what the cause may be? Thanks.

 

[TPLYNCH]

If you still have the automatic hubs, either one or both are shot. Replace with Manual Hubs. Search for Auto Hubs and Manual Hubs for LOTS of posts about them.