Alright so a friend of mine has a Ford Explore with the little switch on the dash for auto 4 wheel, high 4 wheel, and low 4 wheel. When it is in Auto it has no issues drives fine and good. As soon as you turn it to 4 wheel high and start to go all you get is a loud *** clunking noise constantly. Another friend had a similair issue with an AWD explorer that we just pulled the front drive shaft and it seemed to solve the issue. How would I test the driveshaft to see if that's the issue.

 

Take it out.

 

If you are driving in 4Hi on pavement, that clunk is an indicator of drive line wind up..

Continue to do that and you will damage the T/C and/or drive shafts/axles.... Philip