I have a '99 TJ. I hear a loud clunk-clunk when I get up to 35 miles per
hour. 35 miles per hour in gear. No noise when coasting.

I put my jeep up on jack stands and listened. It seemed to be coming more
from the driver wheel than the passenger wheel. I pulled it off and found
nothing clunking around in the brake drum. I've pulled out the drive line.
The Universal joints are fine. I'm going to pull the cover off of the
differentail and take a look inside.

I have the jeep "track lock" in my back diff. I think it's been worn out in
some time. I wounder if this noise has something to do with it.

I'm not much of a mechanic, so any suggestions you have could assist me
greatly. My wife totaled her car this week so I need to fix my Jeep without
the help of a professional if possible.