Air Pressure Test

A NO DRIVE condition may exist even when line pressure is correct. This may be caused by an inoperative band or clutch. An erratic shift may be located by substituting air pressure for fluid pressure.

With gear selector lever in a forward gear position, a NO DRIVE condition may be caused by an inoperative forward clutch, low one-way clutch, low-intermediate clutch or low-intermediate one-way clutch.

A NO COAST condition in manual low (1st gear), could be caused by a faulty direct clutch, direct one-way clutch or coast band. Reverse failure may be caused by a malfunctioning reverse clutch, forward clutch or low one-way clutch. Use the following procedure to perform air pressure tests: Test Procedure

1) Drain transaxle fluid and remove oil pan. Remove valve body cover, oil pump and valve body assembly. See OIL PUMP & VALVE ASSEMBLY under ON-VEHICLE SERVICE . Install Air Pressure Test Plate (T94P-77001-EH) with valve body assembly-to-chain cover gasket.

2) Faulty clutches and bands may be located by applying 40 psi (276 kPa) air pressure to indicated test ports. See Fig 1 .

Fig 1: Identifying Air Pressure Test Plate Ports

Courtesy of FORD MOTOR CO.

If air pressure fails to operate a clutch, or operates clutches simultaneously, remove and, using air pressure, check fluid passages in the clutches, chain cover, front support and driven sprocket support for obstructions.
If air pressure applied to the accumulator passages fails to operate an accumulator, remove and check fluid passages in the accumulator and chain cover for obstructions.