What does the th350 vacuum modulator do?
The vacuum modulator is a vital component of automatic transmissions. It tells the transmission what kind of load is being put on it, allowing the transmission to react with the proper line pressures and shift points.
How do you adjust a modulator valve?
Remove the vacuum line from the end of the vacuum modulator. Use a small slotted screwdriver to turn the adjuster that is located inside of the vacuum fitting. Turn the adjuster clockwise for earlier shifts and counterclockwise for later shifts. Make small adjustments of 1/8 to 1/4 turn at a time.
Can you adjust an automatic transmission?
The technicians at All-Automatic Transmissions understand that problems with your vehicle’s transmission can often be resolved with adjustments or a minor repair. In fact, a simple adjustment can be done without even removing the transmission from the vehicle.
How does a Turbo 400 downshift?
When the throttle linkage reaches a specific point, the cable triggers a mechanical detent valve inside the transmission–allowing it to shift into a lower gear. The Turbo 400 uses an electric switch to trigger a detent solenoid on the valve body to produce the same effect.
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.
How do you raise the shift points on a GM TH350?
Turn the adjustment screw clockwise to raise shift points and counter-clockwise to lower shift points. B&M Vacuum Modulator for GM TH350/TH400 Automatic Transmissions ~ Part # 20234 on Amazon
How do you adjust the vacuum modulator on a GM TH350?
You can adjust the modulator with a small screwdriver. Turn the adjustment screw clockwise to raise shift points and counter-clockwise to lower shift points. B&M Vacuum Modulator for GM TH350/TH400 Automatic Transmissions ~ Part # 20234 on Amazon
How do you upgrade a TH350 transmission?
Another highly recommended upgrade for the high performance TH350 transmission is to install an aftermarket hardened input shaft (left). In a high-performance application, especially where a high-torque engine has been installed and the vehicle will be drag raced with good traction, the input shaft can split and twist at the front lube hole.
What causes shift points to be off on a transmission?
Another possible cause of errant shift points could be the vacuum modulator or a vacuum leak in the line connecting it to the engine. Be sure to ensure a sound vacuum line and connections before wasting money on parts. The vacuum modulator senses engine load from manifold vacuum and moves a fluid pressure valve in the trans accordingly.