Where does transmission vacuum line go?
If the truck has a vacuum hose to the transmission (to the vacuum modulator), the line will be a metal tube attached to the large tube that the transmission dipstick is in. It will come up and connect to a hose that will run to the base of the carburetor.
Do transmissions have vacuum lines?
The transmission vacuum modulator valve determines how much load is on the engine so the transmission can shift properly. It has a vacuum line that connects to the intake and measures the amount of vacuum in the engine.
How does a transmission vacuum modulator work?
The transmission vacuum modulator effectively works by consistently computing the load in your car’s engine with the diaphragm. As soon as a gear change is executed in line with the load demand, the diaphragm pushes the valve to prompt the spring to move in the reverse direction of the diaphragm.
Can a vacuum leak affect the transmission?
The transmission can be controlled. A vacuum leak will cause the engine performance to suffer, causing load and throttle position issues which could affect transmission shifting.
What are the symptoms of a bad transmission modulator?
When you have a bad modulator valve, some or all of the following symptoms will begin to manifest themselves:
- A whistling sound (from a leaking diaphragm)
- White smoke coming out of the exhaust (from a leaking diaphragm)
- Early or late shifting.
- Hard shifts (usually causing the car to jerk)
- A rough idle.
How do I know if my vacuum modulator is bad?
When you have a bad modulator valve, some or all of the following symptoms will begin to manifest themselves:
- A whistling sound (from a leaking diaphragm)
- White smoke coming out of the exhaust (from a leaking diaphragm)
- Early or late shifting.
- Hard shifts (usually causing the car to jerk)
- A rough idle.
How do you test a vacuum modulator on a transmission?
Testing the Modulator
- Block the rear wheels.
- Locate the vacuum modulator on the passenger side rear of the transmission.
- Pull the vacuum hose off the modulator and install the vacuum pump.
- Look for any transmission fluid running out of the vacuum port on the modulator, indicating a broken diaphragm.
What happens when a vacuum modulator goes bad?
The main symptom you will notice is weak engine performance. If the diaphragm of the vacuum modulator were to have a leak in it, you will have a leaky vacuum and your EGR system will shut off. If the vacuum leak is too severe, then you will notice less power in your engine as well as acceleration problems.
Where is the vacuum line in a modulator?
Vacuum line from intake manifold vacuum to the nipple in the center of you modulator. Originally there was a metal line with a short elbow of vacuum line to connect steel line to modulator. Mother of god what an old thread! When setting a modulator, there should be a screw in it from the factory.
How does the transmission vacuum modulator valve work?
by Greg Day. The transmission vacuum modulator valve determines how much load is on the engine so the transmission can shift properly. It has a vacuum line that connects to the intake and measures the amount of vacuum in the engine.
Where is the vacuum modulator on a Ford truck?
Remove the vacuum hose that runs from the intake manifold to the vacuum modulator. The vacuum modulator is on the passenger side of the truck on the rear of the transmission just forward of the tail shaft cover. Pull the hose off and lay it aside. When the hose is removed, look for transmission fluid in the hose.
How does a vacuum modulator work on a Chevy Nova?
The modulator senses the load on the engine via straight manifold vacuum. Maybe think of it like an early computer that could tell what level of acceleration is and adjust the timing and hardness of the shift or shifts. There are valves in the valve body that come in to play to figure shift timing and firmness also.