Switch pitch 400 fluid capacity

Discussion in 'The "Juice Box"' started by Dragdoc, Apr 30, 2020.

  1. Dragdoc

    Dragdoc Well-Known Member

    Just completed a swap from dynaflow to a ‘66 st400 with st300 converter in my 1960 LeSabre. How much fluid should I expect to use?

    All I’ve managed is about 8 quarts. Only 2.5 went in (prior to start up) before it was backed up in the tube and slowly drained out the base and on the shop floor. So maybe 2qts in total? Thats it? Then ran car slowly adding 4qts and put through all gears standing still. OK feeling better - trans guy said typically 10 to 12 qts in the system. So add another 2. Trying for a third and again fluid all over! So 8 is it? Trans guy said stock pan is quite shallow.

    Does only 8 qts seem right?
  2. Here ya go Screenshot_20200430-191608_Chrome.jpg
  3. Dragdoc

    Dragdoc Well-Known Member

    Is that transmission only? Or trans and converter? I realize that the cooling system wont hold much but a 12” converter would easily hold 2+ quarts.
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    The fluid capacity of an ST400 is approximately 23 pints. That's 11 1/2 quarts. A smaller converter will lower that obviously. I would sneak up on that amount and add enough to get the level to 1/4" below the ADD mark as per the factory manual for a cold transmission.

    From the 1967 Buick Chassis Manual, page 74-78, see third column, under "3. adding fluid to fill dry transmission and converter assembly".

    Last edited: May 1, 2020

    BRUCE ROE Well-Known Member

    I put in 12 qts in a TH400 for a dry 13 inch converter, 8 if the converter
    is filled. It needs to be near full to work. Bruce Roe
  6. Dragdoc

    Dragdoc Well-Known Member

    I may have failed to mention, I did NOT pre fill the converter. Old fluid had been pored out of the converter. So a little residual fluid in there, and maybe a bit in the radiator, but I am no where near the 10 to 12 for a “dry”system!

    Why is this not taking more fluid??? I am concerned with going any farther than around the block!
  7. TrunkMonkey

    TrunkMonkey Well-Known Member

    If you start "bone dry" rebult transmission, and a "bone dry" rebuilt/new converter and do not add any fluid to the converter when installing it and the transmission. If you fill 7-9 quarts to the transmission (to prevent puking from the overflow) and start the car, leave in park, the pump should fill the torque converter, then shifting through R/D/L2/L1, while letting the engine idle and light "power braking" with easy throttle increase of RPM, the system should normalize, and then checking the level when warm and idle, keep adding as required.

    Figure just short of three gallons if dry converter and transmission. (11-13 qts)

    If you have run it until it is warm and shifted through the gears, and it reads "normal", drive it a little and check it again.

    When it is "full", it is full. Do not overthink it, nor sweat it if you have near 3 gallons total in the belly of the beastie.
  8. Bens99gtp

    Bens99gtp Well-Known Member

    To just pour fluid out of the converter you wont get all of it out that way normally, I bet there was several it's still in that big girl

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