2 ?s about TH350 trans

Discussion in 'General Automotive Tech' started by Project 64, Dec 2, 2009.

  1. Project 64

    Project 64 New Member

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    My car first
    64 Impala Wagon
    350 ci Engine yr 80-85 truck motor
    TH350 Trans
    Stock rear end as far as I know

    Question 1
    When i take off from a stop at a normal slow speed when it shifts into 2 than 3rd its a very firm to hard shift.
    When I gun it and take off "fast" when it shifts into 2 than 3rd it feels more like it slips into those gears.
    I thought it would be opposite of that, easy shift when taking off slow and firm when hard take off?
    Which way is correct?

    Question 2
    I thought i had a transmission leak because I was filling it up about once a week.
    What I found out is the vacumn line that goes from the transmission to the intake was actually sucking the fluid from the trans and burning it off inside the motor.
    I thought the smoke from the tail pipes was from the engine burning oil but it turns out it was trans fluid.
    Now I have moved the vacumn line to a spot on the carb that has no vacumn and of course now the trans doesnt shift until late and I just cant drive it like that.
    Where should the vacumn line be hooked up at and better yet why would it be sucking the fluid thru the line I thought the line was just for vacumn not suppose to pull fluid thru?

    Any help would be great sorry so long winded
    Thanks
    Bernie
    64 Impala Wagon
     
  2. Steve-E-D

    Steve-E-D Well-Known Member

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    Replace the vacuum modulator where the vacuum line connects to the transmission.
    If the diaphragm inside it is leaking, you will suck fluid through the line.
    Probably the cause of your shifting issues, too.
     
  3. Project 64

    Project 64 New Member

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    Thanks a ton
    I will replace that asap
    Bernie
     
  4. tbirdsps

    tbirdsps New Member Charter Member

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    Don't forget to put the vacuum line back on the correct port on the carb or your shifting problems will continue even with the new modulator.
     
  5. Project 64

    Project 64 New Member

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    Replaced modulator and it fixed both problems
    I still think the trans needs to be rebuilt but it working fine for right now. Hopefully it holds out till i get my other car running so i can park the wagon and restore it correctly
    Thanks again for the help
    Bernie
     
  6. Steve-E-D

    Steve-E-D Well-Known Member

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    (y) You're welcome Bernie. Glad to hear you fixed it.
     

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