I have a 2001 ranger. The door tag has 86 for open rear end 3.73. The tag on the rear end has 3.73 also. My problem is when truck is raised with both rear wheels off the ground wheels turn initially and the stop. If I start the engine the wheels turn initially then stop even though the clutch is still released. It is a 4x2 4cdyl 5 speed, any ideas? Drives fine, but the reason I am checking is I have a vibratiob at speeds over 55mph. New tires and alignment. Most importantly is figuring out the rear end.