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Can I use a solid mount on crossmember for a 4spd?

Discussion in 'The Hokey Ass Message Board' started by Barsteel, Feb 25, 2013.

  1. Barsteel
    Joined: Oct 15, 2008
    Posts: 726

    from Monroe, CT

    Hello -

    Finally got the Borg Warner T-10 into my truck ('57 Chevy 3100), replacing the automatic that used to be in there.

    I ended up having to fabricate a new crossmember, which I did out of 1/8" walled 1 1/2" square tubing. No fancy bends, just straigth across and hung off of the frame flanges.

    Do I need a rubber isolated mount between the tranny and the crossmember? I have one from the T-400, but it appears to be too thick.

    Can I just bolt the tranny to the bare steel crossmember?


  2. EZ Cool
    Joined: Nov 17, 2011
    Posts: 261

    EZ Cool
    Alliance Vendor

    I would not. The least amount of twist when putting the HP to it will likely break the tailhousing on the tranny.
  3. Babyearl
    Joined: May 23, 2008
    Posts: 610


    That solid mount would guarantee a broken tailhousing and transmit all the engine sounds into the cockpit,, asking for trouble.
  4. OoltewahSpeedShop
    Joined: Oct 18, 2007
    Posts: 3,103


    ^^^^^ What they said.... Definitely use a rubber mount.

  5. Sure you can,,but it's gonna shake your truck apart,,if the transmission didn't need something to stop vibration do you really think they would make transmission mounts? HRP
  6. oldolds
    Joined: Oct 18, 2010
    Posts: 3,140


    Solid trans mount only used with solid front or side mounts. It will bust the tranny.
  7. Mr48chev
    Joined: Dec 28, 2007
    Posts: 28,833


    And most likely the first time you really get on it hard.

    It shouldn't be that hard to modify the crossmember to have room for the mount now that you know how much room you need for it. You might even be able to move the crossmember back on the frame a few inches and put a new bracket for the mount on the front side.
  8. You never use a solid tranny mount on an automatic or a stick.
  9. No... it'll brake your tail shaft...

    Even with solid front mounts.. the frame can flex and crack your trans.

  10. Oilcan Harry
    Joined: Mar 3, 2001
    Posts: 906

    Oilcan Harry
    from INDY

    Don't do it! A buddy broke three 350 turbos before he figured out his mistake. Either rubber mounts engine and tranny, or solid engine and tranny. Don't mix 'em.
  11. ninosdad
    Joined: Aug 12, 2012
    Posts: 102


    Rubber mount it even if you have to fab some mounts. We once mounted a M22 on a home made crossmember then used a piece of tire on a flat plate bolted up but I'm sure beter options are around now...that was about 1970
  12. 32-3 WINDOW
    Joined: Nov 23, 2005
    Posts: 1,696

    32-3 WINDOW
    from utah

    you will bust your tail , and im meaning the wrong way , use a rubber mount or biskets
  13. black 62
    Joined: Jul 12, 2012
    Posts: 1,895

    black 62
    from arkansas

    seems we have reached a consensus...
  14. Yup!

    Stick a fork in this thread 'cause it's done! ;)
  15. lht
    Joined: Jan 18, 2013
    Posts: 243


    you can use solid tranny mount but you have to run solid motor mounts too i drove a amx with a bbc 4-speed for 35 years set up like that beat the livin snot out of it street and track never no tailshaft problems car didn't shake too bad
  16. ^ ^ ^ This just tells me you got lucky!
  17. Barsteel
    Joined: Oct 15, 2008
    Posts: 726

    from Monroe, CT

    Awrighty then...already started fabbing a crossmember to use the T400 rubber mount...thanks for the input...
  18. pitman
    Joined: May 14, 2006
    Posts: 5,041


    If it's too close in height, just overlap three cut pieces or Zee it to get the depth you need. That's a good tube choice.
  19. lht
    Joined: Jan 18, 2013
    Posts: 243


    50 or 60 mid 10 second passes and a whole lot of street beating i don't think luck was a factor people tear stuff up runin solid on tranny and not on motor been drag racin a long time never ran rubber mounts racin
  20. scottybaccus
    Joined: Mar 13, 2006
    Posts: 4,109


    He didn't get lucky. He had the car set up right. An alky pro-mod uses solid mounts all-around, and 2500 HP doesn't break anything. In fact, with mid and front plates, a tranny mount isn't even necessary. Want proof? I'll send you the pictures.

    OP, if you have rubber mounts forward, you need rubber mount on the trans. If you want something stiffer, try urethane mounts. If you are breaking mounts, you need to make sure everything is aligned, correcting any issues, and then you can use limiting devices to control powertrain motion under power. A lateral brace from the block to the frame helps, but the old trick of drilling through the rubber motor mount, and installing a bolt only tight enough to eliminate slack, really works well.

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