I have an 02 2wd with axle code H9. I alwaya thought i had an open diff and never used limited slip gear oil. I have the 4.6L with 35" tires and 200,000 miles so i can only break them loose off the pavement. I believe only 1 wheel gets power off road but i do not hear any bad noise or feel anything. How would i check to make sure the LS is working properly? How do i check the clutch pieces in the diff for wear?