Disconnecting TH400 from 455

Discussion in 'Wrenchin' Secrets' started by BigBlocksRule, Nov 5, 2018.

  1. BigBlocksRule

    BigBlocksRule Well-Known Member

    Ok Buick brethren, not sure why I am having this problem so hopefully someone can advise. I have removed the six tranny to block bolts, and the three flywheel to torque converter bolts, but for some reason the motor and trans are acting like they are still bolted together. A buddy said to use a pry bar and try to separate, but since this is the first time I am removing the block from the tranny I am a bit apprehensive. That being said, what am I missing? Thanks!
  2. TrunkMonkey

    TrunkMonkey Well-Known Member

    You have to make sure the input shaft is not binding. Raise and lower the transmission jack a small amount at a time and shake the snot out of the tail shaft, and it should let go.

    Check and see if the torque converter will spin on the crank, it will not if it is in a bind or if the TC is stuck to the crank.

    I will use a couple of long grad 8 bolts on the bell housing so that when I get vigorous with the shaking, I don't worry about the transmission coming loose and falling of the jack.

    Then I stabilize things and remove the bolts. I also use the bolts as "guides" to help put the transmission back in.

    I do not like using pry-bars unless as a last resort, and then I use wood or softer metal as a "padding/bearing surface" to spread the load protect the parts from gouging and such.
    Dan Gerber and GS464 like this.
  3. johnriv67

    johnriv67 Well-Known Member

    You need a damn ton of heat. Buy a propane torch for about $30 at your local autozone, NAPA, Oreillys, or whatever and heat the dowel pins in each side of the transmission. It's the only way it worked for me
  4. 1970 STAGE 1

    1970 STAGE 1 Well-Known Member

    You are stuck on the dowel pins, WIGGLE THE TRANS OFF OF THEM. Be careful when it breaks loose.
  5. BillA

    BillA Well-Known Member

    I used a come-along to apply slight pressure to the tail of the transmission and then put a little heat on the transmission bell. Popped loose just enough to slide it off the rest of the way. First, make sure both the engine and transmission are supported independently and they're not binding.

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