I use this tool to adjust the backlash in the crown wheel and pinion,  This was on the back axle for the Lincolnshire Group’s trial car.  The tip of the tool should only indicate 1/16th of an inch movement. This equates to 0.004 inch at 7 inches from the center.  It is possible to do this on  the car through the greasing hatch behind the front seats.

I started by removing the front seats to make more room to work.  The rear axle was jacked up and put on axle stands, essential when working under the car, then the diff oil was drained and the two adjustment panals removed.  Inside the car the floor covering and tunnel cover were removed.  Removing the greasing hatch over the torque tube anchor exposed the universal joint. one nut was removed and the 7 inch gauge strip bolted on.  The crown wheel anchor bolt was fitted in the oil filler hole, this is essential to getting a true reading on the gauge.  Having checked the adjusting collars were up to the bearings but not over tight the movement of the torque tube was checked.  The brakes were applied and the car put in gear.   The movement needs to be 1/16th of an inch at the 7 inch mark.  If it needs adjusting that is achieved by winding the adjusters in or out as required.  See more here.


If re-building an axle then the meshing needs to be checked with engineers marker.  It involves fore and aft movement of the torque tube with shims and side to side with the rotary adjusters.