Automatic Transmission Vacuum Modulator
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Pro-King Automatic Transmission Vacuum Modulator

Part No. MD-48 Warranty Details  

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Fully adjustable vacuum modulator to maintain accurate shift points.
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O.E.M. Replacement:Yes
Transmission Manufacturer:GM
Transmission Model:250/C; 350/C; 400 (3L80)

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Pro-KingAutomatic Transmission Vacuum Modulator
 
3.0

(based on 1 review)

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Reviewed by 1 customer

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3.0

Worked as advertised

By 

from Laurinburg NC

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      Comments about Pro-King Automatic Transmission Vacuum Modulator:

      No issues with this product

      • Was this a gift?:
      • No

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      16 Questions | 24 Answers
      Displaying questions 1-10Previous | Next »
      • Q:

        are these pre adjusted 6.2 turbo 400 trans 1984 p-20 stepvan needs lot of pedel to shift
        Asked on 10/1/2011 by ed from fl

        1 answer

        • CUSTOMER CARE

          A:

          When a clutch pedal feels that way, it is an indication of air in the system, and when this happens, it makes it hard to operate the clutch properly because it engages even with your foot almost all the way to the floor, at times you may not even be able to place your car/van in gear due to this problem. To prevent this, you need to bleed the clutch on your Chevy van.

          Answered on 10/11/2011 by Auto Part-er Andy from AAP
      • Q:

        will not shift into high gear all the time be with the modulator. i have a 1986 chevy p-30 chassis with a th400 and a 7.4 liter motor.
        Asked on 6/6/2011 by rick from md

        1 answer

        • CUSTOMER CARE

          A:

          This might be the problem. However, I would suggest taking your vehicle to a certified mechanic for a proper diagnosis before buying and having parts installed that may not (solve/be) the problem.

          Answered on 6/21/2011 by DIY Daniel from AAP
      • Q:

        Where is this modulator on a 84 chevy caprice with a 700r transmission
        Asked on 5/31/2011 by Rich from TN

        3 answers

        • CUSTOMER CARE

          A:

          The modulator valve is a part of the transmission vacuum. Inside the canister of the vacuum modulator.

          Answered on 6/2/2011 by Just Ask Jacob! from AAP
        • A:

          Look at the transmission on the passenger side of the car. The modulator valve is in attached to the side (passenger side in your case I think) of the transmission, right about 2/3 towards the rear of the transmission., right before the tail of the transmission bolts to the main body of the transmission. It's a round piece about 2 1/2" diameter and has a vacuum hose going into it.

          Answered on 8/5/2011 by chuck10101 from Delta, Alabama
        • A:

          Let me know when you find that modulator on your 700r..... GM never used a modulator valve on the 700r4, the line pressure is controled by the detent cable that hooks to either the carb or throttle body depending on application and the governor driven by the tailshaft controls your shift points....

          Answered on 12/5/2014 by Napa Jeremy from Under the Hood, IL
      • Q:

        where is the automatic transmission vacum modulator at under the hood of a 1995 ford trasus
        Asked on 3/21/2011 by Anonymous from santee

        1 answer

        • A:

          it should be located under your car directly under the passenger side. crawl under the passenger side and look at your transmission, you should see it there.

          Answered on 4/22/2011 by john from north carolina
      • Q:

        my suburban down shifts when i let off the gas would this be my problem
        Asked on 3/20/2011 by hal from spartanburg , sc

        1 answer

        • CUSTOMER CARE

          A:

          This could possibly be the problem. However, with out the presence of your vehicle we would not be able to properly diagnose it nor provide you with a 100% answer.

          Answered on 3/21/2011 by David the Dynamite Parts Guy from AAP
      • Q:

        my truck shifts into gear kinda hard sometimes i have changed trans fluid and filter can this be a problem also
        Asked on 2/21/2011 by Anonymous from florence sc

        1 answer

        • CUSTOMER CARE

          A:

          I would suggest taking your vehicle to a certified mechanic for a proper diagnosis before buying and having parts installed that may not (solve/be) the problem.

          Answered on 2/22/2011 by David the Dynamite Parts Guy from AAP
      • Q:

        How do you adjust it?
        Asked on 1/16/2011 by big red from columbus, ga

        2 answers

        • CUSTOMER CARE

          A:

          For step by step instructions I recommend that you go to your nearest Advance Auto Parts store and purchase a repair manual.

          Answered on 2/11/2011 by David the Dynamite Parts Guy from AAP
        • A:

          Turn adjusting screw out for earlier shift, in for later shift.

          Answered on 7/13/2014 by RocketBill from Purvis, Ms
      • Q:

        I have fluid leaking out of a circular thing on the transmission on the passenger side of my 78 C30. What is this thing?
        Asked on 12/30/2010 by Anonymous

        2 answers

        • CUSTOMER CARE

          A:

          With out the presence of your vehicle we would not be able to properly diagnose it nor provide you with a 100% answer.

          Answered on 1/2/2011 by Ron the Auto Parts Rebel from AAP
        • A:

          Is the fluid transmission fluid? (Transmission fluid has a distinctive odor.) Is the vehicle not shifting properly? If both answers are, "Yes", this is likely the part that is leaking and needs replaced. If I remember correctly the transmission vacuum modulator is the only round part attached to the transmission on that side other than a couple of lines a few inches above it, but without looking at it I can't say for sure.

          Answered on 8/31/2014 by More Shade-tree than Mechanic from Rock Island, IL
      • Q:

        Would this modulator cause a vehicle to not shift at all??
        Asked on 10/25/2010 by GMAN

        2 answers

        • CUSTOMER CARE

          A:

          This could cause the transmission not to shift at all; however, with out the presence of your vehicle we would not be able to properly diagnose it.

          Answered on 11/15/2010 by Ron the Auto Parts Rebel from AAP
        • A:

          To check if the modulator may be the problem, pull the vacuum line out. If transmisson fluid runs out or if there is transmission fluid in the tip of the vacuum line, the diaphragm is ruptured and the modulator will need to be replaced. This may fix your shifting problem. However, without more information it is impossible to diagnose the problem.

          Answered on 8/31/2014 by More Shade-tree than Mechanic from Rock Island, IL
      • Q:

        Where is this modulator located on my 1982 GMC K2500??
        Asked on 10/25/2010 by GMAN

        2 answers

        • CUSTOMER CARE

          A:

          The Vacuum Modulator is usually located on the side of the transmission. However with out the presence of your vehicle we cannot provide you with a 100% answer.

          Answered on 11/15/2010 by Ron the Auto Parts Rebel from AAP
        • A:

          Passenger side right by the tailshaft has a small hose on it, and has a half inch wrench bolt an small bracket!

          Answered on 9/23/2013 by Dj from Bingo
      Displaying questions 1-10Previous | Next »

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