The only Ford transmission that uses a vacuum modulator is the A4LD. It’s used in the 1985 by way of 1991 F-150. The transmission has three speeds and is considered mild duty. The vacuum modulator takes the place of the TV cable. It controls up or down shift when energy is being applied. The TV stands for throttle valve. The modulator does the job of the TV cable by increasing the stress on the second and third upshift spring, preventing bypass until a higher strain is obtained permitting for a better shift point.
Ford F-150 Transmission Modulator Installation Instructions
1. Elevate the passenger facet of the truck by inserting the floor jack behind the tire and on the frame. Place jack stands below the truck, one simply to the rear of the ground jack and the other just forward of the leaf spring. Take away the vacuum hose that is plugged into the again of the vacuum modulator, which is positioned on the passenger facet of the transmission, subsequent to the tailshaft.
2. Take away the maintain-down clamp securing the modulator to the transmission by eradicating the bolt within the bracket utilizing a wrench. Pry the vacuum modulator out of the transmission housing. Be sure that the rod comes out with the modulator or pull the rod out if it remains. It’s long enough to get a maintain on it.
3. Examine the new vacuum modulator and make sure it has the same colour circle round its outdoors circumference. The color denotes the vacuum pressure essential to actuate the module. Take a look at the 2 O-rings on the shaft that get inserted into the transmission and make sure they aren’t misplaced or torn. Install the rod finish into the vacuum modulator and insert the modulator into the transmission. Push it hard enough for the O-rings to enter the transmission for a great seal.
4. Set up the hold down bracket and bolt and tighten with a wrench. Install the vacuum hose on the modulator. Lower the truck.