POTENTIAL CAUSE(S)

CHECK THESE FIRST:

1. MALFUNCTIONING SHIFT INDICATOR
Have shift indicator professionally repaired.

2. LOW TRANSMISSION FLUID LEVEL
Add transmission fluid if necessary.

CHECK THESE NEXT:

3. CLOGGED TRANSMISSION FILTER
Replace or clean transmission filter.

4. PARKING BRAKE ENGAGED
Release parking brake.

CHECK THIS LAST:

5. FAULTY DIFFERENTIAL
Have differential professionally repaired.