Discussion in 'Troubleshooting & Diagnosis' started by Lou6t4gto, Jan 2, 2018.

  1. Lou6t4gto

    Lou6t4gto Veteran Member

    Aug 18, 2010
    Ocala, Fla
    Had my 73 Z28 for over 40 years. I am just now putting in a 700r Trans. I've got the trans bolted to the engine, cross member under the tail shaft, BUT... the tail housing where the driveshaft slips into is 3/4" OFF CENTER to the passenger side ! I slipped in the drive shaft, and if I leave this alone the u-joint will rap on the floor under acceleration. 3/4" is an awful lot to be off center. I checked my wheelbase, frame rail to rockers, frame rails to rear spring perches, and everything comes up perfectly straight. WHAT would make the engine/trans sit cockeyed in the sub frame like that ??? (never noticed it with the th350 being so much shorter) HELP !
  2. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

    Nov 4, 2004
    Ringgold, GA
    Mine was off at least that much. I just shoved it over as far as I could and tightened the bitch down, no problems. I think you'll find that just about all are offset some to the passenger side.
  3. budro6968

    budro6968 Veteran Member

    Apr 2, 2016
    Jax Florida
    Are the motor mounts good or shifted?
  4. Smokey15

    Smokey15 Veteran Member

    Aug 13, 2017
    I had that with the TH400 in my wife's '71 Z/28. I loosened the crossmember bolts, and motor mount bolts. Then I shifted the transmission to where it needed to be. Started the bolts in a bit. The tightened everything front to back.
  5. BonzoHansen

    BonzoHansen Administrator Lifetime Gold Member

    Something moved. it's not like it had an offset shaft
  6. G72Zed

    G72Zed Veteran Member

    Sep 8, 2015
    Those cars had approx 1/2 inch of engine centreline offset to the passenger side to compensate for driver weight, if you force the trans mount to much to the driver side to "recenter" the trans output, you may negatively effect the parallelism of the drive train to rear and induce less than optimal drive shaft compound angles.
  7. Lou6t4gto

    Lou6t4gto Veteran Member

    Aug 18, 2010
    Ocala, Fla
    Every "Mount in the car has been replaced, (all Good). there is no just shoving it over, the way it is, it drops right onto the cross member holes. the cross member is bolted to the rails (cannot move), the holes in the trans mount pad are orig,( cannot move), It Must be that it has Always been that far off.( the trans pad was NEVER "centered" between the rails) But , like I said, I cannot Leave it like that , the trans pan is almost touching the pass side tunnel, and the front u-joint will hit the floor tube. going to Have to alter the holes in the cross member pad to move the Trans mount about 3/8" to the driver side.
  8. Smokey15

    Smokey15 Veteran Member

    Aug 13, 2017
    If it's that bad, there may be something wrong with the motor mounts.
    Zstar likes this.
  9. SRGN

    SRGN Veteran Member

    Feb 20, 2009
    Central NJ
    Make sure the motor mounts are correct and the frame side mounts are correct. Also make sure the frame side mounts aren't switched side to side.

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