Manual Drive Train & Axles
Work Example 12

WorkKey Level: 4
NATEF Automotive Tasks: III.E.1.1, III.E.3.1

You have modified your car and are having a vibration problem.  You measure the transmission angle and the rear axle differential angle of your car.  The transmission angle is 5/8 degree and the differential angle is 1 3/8 degree.  A difference greater than ½ degree is too large and will cause vibration.  You will use shims to correct the angle problem.  One shim will change the transmission angle 1/8 degree.

1.  What is the difference in the measurement of the transmission angle and differential angle?

 2.  How many shims should you use to correct the problem?

Solution:

1.  Difference = 1 3/8 – 5/8
     Difference = 6/8 or ¾ degree

 2.  3/4 - 1/2 = 1/4
      The difference is between 1/4 and 3/4 degrees.
       If each shim changes the transmission angle by 1/8
       degree, then:
       (1/4)/(1/8) = 2 and (3/4)/(1/8) = 6
       You should use between 2 and 6 shims to correct the
       problem.