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If you look at the passenger side of the transmission towards the back you will see it,
It will have a vacuum line hooked to it, unhook it and now you will see 1 bolt in a horse shoe clamp that holds the modulator in. Remove it and pull the modulator out of the trans. being careful not to drop the little 1 inch PIN that is in the end of the modulator valve. some fluid will come out, That's okay. Now install small pin into new modulator valve and push it back in the trans. Install bracket and bolt then the vacuum line. That's it your done. Let engine get hot then check the Transmission Fluid while engine is running on leval ground, Add as needed.
Jack up and support the rear of the vehicle when you do this job and you won't lose more than a drop of ATF.
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Where is the vacuum modulator on a 1995 Chevy Silverado?
If your speaking of the vacuum modulator for the transmission, they no longer use them on the transmissions with overdrive and electronics. The powerglide, turbo 350 and turbo 400 used to use them.
1980 turbo 350 shifts into drive too soon?
Check the vacuum source to the vacuum modulator. If it's good, try a new modulator.
How do you change the vacuum modulator on a 1978 Chevrolet C20 pu 350 AT Turbo400?
The vacuum modulator is on the passenger side under the cooler lines on a turbo 400. It's held in with one bolt that goes through a clamp that holds the modulator in. To change it put a drain pan under the modulator, pull the vacuum line off it, remove the bolt and clamp, pull the modulator out. Make sure the o-ring seal comes out with it, be sure there's a new o-ring on the new modulator and put it in, replace the clamp and bolt that holds it in and hook up the vacuum line (if it's an adjustable replacement modulator you might need to use a little bit longer rubber line if it has a steel line running down with a short rubber line at the end since some of the old turbo 400's originally had a big canister modulator and the new one will probably be smaller). Then start the engine, check for leaks and refill the transmission as needed. Same procedure on a turbo 350 but the modulator is in the rear on the passenger side pointing towards the back of the car/truck on a turbo 350.
How do you tell a turbo 400 from a 350 turbo?
The TH 400 has the vacuum modulator attached to the passenger side of transmission.The TH 350 has the vacuum modulator attached to the rear of transmission.The transmission oil pan on the TH 400 is anything but square.
Which way do you turn the screw on modulator valve On a 350 turbo trans to make it shift quicker on low vacuum?
the modulator valve does not have a screw, however, the modulator located outside the modulator valve may or may not have one.
Where do you run the vacuum line from the turbo 400 trans modulator to an edelbrock performer 800cfm carb?
When you get ready to run the vacuum line from the turbo 400 trans modulator to an Edlebrock Performer 800 CFM carb, attach the vacuum line for the transmission vacuum modulator to the bottom constant vacuum source or the plug that is below the throttle plate. After that, install the vacuum advance to the port that is signaled or right above the throttle plate. Once that is completed, install the large vacuum line to the back of the carb for the power brake.
How do you adjust a 350 trany?
There is no adjustments to a 350 Turbo Transmission (GM). The only external thing that would cause shift problems is the vacuum modulator on the side. This is replaceable easily. Check for proper vacuum signal to the modulator. Make sure there are no holes and or kinks in the vacuum line from the engine to the modulator. If none is found, replace the modulator for shift complaints. If it is slipping, the tranmission will require removal and overhaul. This transmission uses wet clutch plates and automatically compensates for wear in the plates to a certain point.
Does the vacuum Modulator on the turbo 350 need to be hooked straight to manifold vacuum. Or can you use any vacuum port on the carb.?
It must be connected to a full-time vacuum source such as the intake manifold.
Can you run a vacuum pump to the vacuum modulator on a 350 turbo transmission?
No because this will not be the proper signal from manifold vacuum that tells the transmission what kind of throttle position and load the engine is under.
How do you tell a turbo 350 transmission from a turbo 400?
The TH 400 has the vacuum modulator attached to the passenger side of transmission.The TH 350 has the vacuum modulator attached to the rear of transmission.The transmission oil pan on the TH 400 is anything but square.
How do you replace the modulator valve on the transmission of a 1988 Chevy 1500 pickup?
modulator is round and located on the drivers side of the transmission. modulator unscrews from the transmission if it is a 700 R4 It unbolts with 2 7/16 bolts if it is a turbo 350 Unplug the vaccum line remove the modulator replace with new modulator hook up new vaccuum line
How do you remove the modulator on a 1967 Chevy truck?
Assuming this is a PowerGlide or Turbo-350 automatic transmission vacuum modulator, to minimize fluid loss jack up the rear of the truck and support with suitable jack stands, place a drip pan under the modulator, pull off the vacuum line from the modulator, remove the small bolt and clamp holding the modulator in place, gently twist and pull the modulator out taking care not to lose the small actuator pin inside. Keep the dirt from entering the opening. Install the new modulator with a new o-ring.
