How to know if my 400 transmission converter is bad

Discussion in 'The "Juice Box"' started by chrisk, Oct 23, 2015.

  1. chrisk

    chrisk Well-Known Member

    Yeah, I have a 67 Skylark and when I drive my 400 transmission has been giving me some problems, when I'm driving, it is straining like it doesn't want to shift gears. It sounds like it's just staying in low gear the whole time. Not sure why. I'm thinking it may be the converter but not sure how to tell.
    Last edited: Oct 23, 2015
  2. Jim Weise

    Jim Weise 1000+HP

    What are the symptoms?

  3. chrisk

    chrisk Well-Known Member

    I edited my post. Thanks
  4. SteeveeDee

    SteeveeDee Orange Acres

    Does it ever upshift, like at some higher than usual RPM? We need a pile more information in order to make a good diagnosis.
  5. Jim Weise

    Jim Weise 1000+HP

    2 quick things to check

    Fluid level- With the car fully warmed up, on level ground, running and in park, insure the fluid level on the stick is no lower than the "add" mark, and preferably between the Add and the Full.. Not over Full Also note the color and smell of the fluid.


    ON the passenger side of the transmission, near the dipstick, you will see a round canister with a vacuum line attached. That vacuum line is metal, if it's all still stock. With the car off, pull that line off the modulator, and start the car.. then make sure the line sucks your finger in, as you cover it. Don't burn yourself on the exhaust.

    Let us know what you find.


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