Th400 modulator valve

How to Test a TH4Vacuum Modulator by Don Bowman The TH4is an early model, non-computer-operated transmission widely sought after by car enthusiasts for its internal strength. OEM good used th4modulator valve , the notch in the 2nd picture is the way it was made from the factory. When the diaphragm inside the modulator valve ruptures, transmission fluid is drawn up to the engine like liquid through a straw via the steel vacuum tubing. When burned in the engine, this transmission fluid produces blue smoke from the tailpipe. Fits GM TH3and TH4automatic transmissions.

This works well for superchargers and on diesel motors without a vacuum regulator.

This modulator uses a 700Rthrottle valve cable. The document has moved here. The modulator is connected to the engine by using steel tubing and rubber hosing. TH4modulators are a type of valve that is designed to assist in controlling shift patterns.

When there is more vacuum from the engine, the transmission will have an easier shift feel to it. After the boost valve modification, you can install an aluminum plug that blocks the modulator valve in place. The original bolt and bracket from the vacuum modulator holds the aluminum plug in place. The TH4has a over-ride shift that will shift out of low gear even if you have manually selected low. Valve body mods, automatic shifts.

As a part of the transgo reprogramming kit, you can remove that spring to firm up shifts. Replaces the vacuum modulator with a direct acting valve connected to the throttle. Adjustable Modulator , GM TH35 TH4, Push-In, Each. Supplied adjusted for normal shift points. On some models there is a. The vacuum modulator is a vital component of automatic.

Some cars have a simple cable linkage connected to a throttle valve in the transmission. The further the gas pedal is presse the more pressure is put on the throttle valve. Other cars use a vacuum modulator to apply pressure to the throttle valve.

For your car to shift appropriately, the automatic transmission vacuum modulator functions must analyze if your engine works properly to execute such a command. It does this in two different means.

Even though some car makes and models have simple cable linkages attached to a throttle valve in the automatic transmission, it still serves the. We know our parts and products. I use for a tranny vacuum modulator line? THIS IS AN EARLY EDITION OF TH4DISASSEMBLY. Use a magnet to remove the vacuum modulator valve (15) from the case bore.

Remove and discard the o-ring. A strong magnet usually pulls the valve from the case. Check valve phasing when solenoid is applied and released. Install o-ring on solenoi install into case. DO NOT install any gaskets on the case or valvebody!

Start all valve body bolts before tightening! On the aftermarket replacement modulator valve that AAP tried to sell me has an. Re: Quick question about Th4modulator valve mod just remember that when you remove the gov. The function of a transmission modulator valve is to regulate the timing of gears shifting. It works alongside the throttle, which indicates when the vehicle hits a speed that necessitates a gear shift.

An indication of a faulty transmission modulator valve is the inability of an automatic transmission to shift gears. But it doesnt shift as hard any more. I have always assumed that my 3. Do you adjust the 3modulator valve the same way you do the 400?

Is the screw inside the nipple when you remove the vaccuum hose? Includes highest quality Duraprene pan gasket and flat dacron filter. It is very important to change your TH4filter on a regular basis. Figure 4) Reinstall hold down clamp and bolt. This low vac modulator will give you an earlier (and smoother) shift from first to secon and second to third.

It will stop irritating late shift issues in the TH3and TH400. Insert brake valve and spring into the modulator valve bore. This should slide in and out freely. I need to get or cut my spool valve , so the new modulator will slide into the trans! It is highly regarded for its supreme durability.

I told Craig Railsback (the guy at BDS who designed the valve originally) what I had done with it and he said I was nuts and would ruin my transmission. Either way, both technologies have the same function. When we talk about the load on the engine, we are referring to how hard it must work just to maintain its functionality. Also check your modulator valve , it's in the case, behind the vacuum modulator.

Transmission help Neede th4not shifting. If the governor is working a. Our Stage TH4is a heavy duty rebuild with valve body and hydraulic improvements, rollerized rear thrust, heavy duty intermediate snap ring, and OEM pan.

Identical to original equipment. Necessary for proper transmission operation. This vacuum modulator valve is a must-have for all TH3and TH4automatic transmissions.

Related Products from Hurst Performance. Usually a bad or failing EGR vacuum modulator will. Hi Scotty and Welcome to ChevyTalk.