Hello, I have an 02 mercury mountaineer awd. It's making a clunking/clanging sound when going in forward and reverse and it gets louder when turning. Just replaced driver cv axle, changed fluids on front and rear differential also put the stiction modifier in rear. It only does it on the ground assuming it's putting a load on it. Won't do it on a lift. Any ideas what might be causing it. Any info would be great. Tires are same size also.

 

DId the clunking happen after you changed the axle ? If so, you have the CV in a bind during install. If it clunked before and after, i would look at the drive shaft universal joints, and maybe inside the rear brake hubs for damaged parking brake shoes.

 

It did the noise before install of the cv axle. It almost sounded like that's what is was coming from so that's why I changed it. Brakes are all brand new rotors and pads. Checked wheel bearings they seem fine also. It will only do it under load, it won't do it on a lift. Mind boggling.

 

try to wiggle the drive shaft into the rear axle at the universal joint. See if you have excess play in the pinion bearing.