LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 1987 >> Forward Control 4.8 T, Standard >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Overhaul - THM 400 >> Testing >> Vacuum Modulator Check >> Atmospheric Leak Check

Atmospheric Leak Check

Apply soap bubble solution to vacuum connector pipe seam (crimped upper-to-lower housing seam). Use a hose and blow air pressure into vacuum pipe and check for leaks. If leaks are present, replace modulator.

CAUTION: Air pressure over 6 psi (.4 kg/cm2 ) may damage modulator.