Vacuum Modulator

NOTE: A faulty vacuum modulator can cause:

Harsh upshift and downshifts.
Delayed upshifts.
Soft upshifts and downshifts.
Slips in "L", "D" and "R".
Transmission overheating.
Burnt transmission fluid.
1. Remove modulator. Hold modulator so vacuum fitting points downward. Replace modulator if full of transmission fluid.
2. Connect vacuum pump. Apply 20 In. Hg of vacuum. Ensure modulator operates and holds vacuum. Replace if necessary.