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Technical transmission question.... do I have a problem?

Discussion in 'The Hokey Ass Message Board' started by evobuilder, Jul 6, 2014.

  1. evobuilder
    Joined: Aug 27, 2007
    Posts: 432

    evobuilder
    Member

    I just installed a BRAND NEW TH350 in my coupe and it works great. Recently I was installing my new Lokar shifter and noticed that while I was shifting the trans back and forth, forth and back, etc. that all of the sudden, the car rolls as if its in neutral while in park.

    Is that normal? It doesn't seem right, but I guess it could be, that the continuous shifting of the transmission fron P to 2 and back and forth with the motor off (aka no vacuum) could cause this scenario..... but again, it seems really odd.

    Any thoughts
     
  2. saltflats
    Joined: Aug 14, 2007
    Posts: 12,592

    saltflats
    Member
    from Missouri

    Sounds like you should check adjustment again.
     
  3. Grahamsc
    Joined: May 13, 2014
    Posts: 466

    Grahamsc
    Member
    from Colorado

    Rolls as in a few inches is normal.
    It has to catch the next cut out in the parking paw.
    If it rolls more than a few inches you have something out of adjustment
     
  4. evobuilder
    Joined: Aug 27, 2007
    Posts: 432

    evobuilder
    Member

    saltflats..... I would tend to agree with you, but if I am not messing with the shifter, the trans works as it should. when parked.... if I mess with shifting, then yes, the "neutral scenario" appears.
     

  5. evobuilder
    Joined: Aug 27, 2007
    Posts: 432

    evobuilder
    Member

    but I am tending to agree that I have an issue..... just not sure if its with the shifter, or within the trans
     
  6. saltflats
    Joined: Aug 14, 2007
    Posts: 12,592

    saltflats
    Member
    from Missouri

    Will it go into park if you unhook the shifter.
     
  7. evobuilder
    Joined: Aug 27, 2007
    Posts: 432

    evobuilder
    Member

    I will test that next..... it s aLokar cable shifter, so it could very well be some adjustment with the new shifter, I just think its weird that once vacuum is built up, it shifts perfectly, operates perfectly, etc.
    Like I said, its a BRAND NEW TH350 from Speedway so it should work as it is intended.
     
  8. saltflats
    Joined: Aug 14, 2007
    Posts: 12,592

    saltflats
    Member
    from Missouri

    The vacuum has nothing to do with the park it is controlled buy the linkage.
     
  9. evobuilder
    Joined: Aug 27, 2007
    Posts: 432

    evobuilder
    Member

    this is helpful, just seems weird that I can drive the car and PARK works perfectly..... but after sitting in my garage and eff'ing with the trans, it doesn't recognize PARK. If I fire it up.... the trans works as it should.
     
  10. stimpy
    Joined: Apr 16, 2006
    Posts: 3,546

    stimpy

    as soon as you pull the selector into reverse the park pawl ( pin) which is mechanically connected will pull out of the locking ring like Grahm said and unless its lined up close enough it will not slip back and lock and this locking ring is on the final drive drum so you have to move the car /rotate the tire a few inches ,( this is why your DD rolls a little bit when you park it ) the pin is released and then pops in place when it rolls or the slack is taken off the driveline
    when unlocked even starting it until it ( final drive ) moves, it will not drop in place till the wheels rotates a few inches to align the slot then the pin is pushed in by the spring , if its not going in after the wheels move then you could have bent or burred the pin .or burred the pawl /drum
     
    loudbang likes this.
  11. evobuilder
    Joined: Aug 27, 2007
    Posts: 432

    evobuilder
    Member

    that's what is soo crazy.... I understand the rules of mechanics, but I am seeing something different than the common answer. I just fired the car up.... drove around the block, and the trans works perfectly.... and even park, holds the car on a hill. So I have something odd going on, I think.
     
  12. evobuilder
    Joined: Aug 27, 2007
    Posts: 432

    evobuilder
    Member

    here's the big question..... I can accept that I have an adjust ment issue getting into PARK. I can work on that.... but if parked in my driveway..... why would it move in R, N, D, 2 and 1.... is that normal? I doesn't seem right to me. Anyway.... I will get PARK adjusted tomorrow, as for the rest of the positions..... I am still not clear.
     
  13. Commish
    Joined: Jan 9, 2010
    Posts: 379

    Commish
    Member
    from NW Ok

    If I am understanding you right, then yes, it is normal for it to roll in any gear position other than park, setting in your driveway.
     
  14. Andamo
    Joined: Jan 10, 2006
    Posts: 523

    Andamo
    Member

    When the motor isn't running you have no fluid moving in the converter and transmission so whatever position you have the gearshift selector in, other than Park, will not have any sort of power transmission. Park is the only gear that has a mechanical method of engaging.
     
  15. why would it move in R, N, D, 2 and 1.... is that normal? I doesn't seem right to me. Anyway..


    Park is a mechanical locking inside the trans, anything other than park lets the trans move. Engine off and there's no fluid pressure and the internals will free wheel. that is exactly why these transmissions need the mechanical locking of park.

    Yes this is perfectly normal - so you need to adjust your thinking on this.
    There's no way to push start a th350

    The vacuum signal tells the trans how hard you are accelerating or how hard the engine is working. What that does is adjust the hydraulic pressure inside the trans as long as there is pressure being created by the engine spinning the pump.
     
    Last edited: Jul 7, 2014
  16. OLDSMAN
    Joined: Jul 20, 2006
    Posts: 2,422

    OLDSMAN
    BANNED

    It is normal for an automatic transmission to move when shut off in any of the gears except in park. You have no problems with the transmission or linkage adjustment. Just drive the car and have fun
     
  17. I just invented a new word! Hydrochondriac. :) Fear that there is always something wrong with your GM automatic trans.
     
  18. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    ^^^^^^^^^^^:D:D:D:D:D:D^^^^^^^^^^^^^
     
  19. I had a similar situation with a lokar shifter in the past. It ended up being an adjustment issue and the park scenario was a normal condition. As others have said, Park is strictly a mechanical operation, no fluid pressure involved in engagement.
     
    Last edited: Jul 7, 2014
  20. Funny funny funny
     
  21. saltflats
    Joined: Aug 14, 2007
    Posts: 12,592

    saltflats
    Member
    from Missouri

    You don't have to gut a TH350 to check the park operation just pull the pan but if you move the lever on the side of the trans and park works no need just play with the adjustment of the shifter. Is there a chance that there is a lever that comes with the shifter that was not changed out on the tranny?
     
  22. parking brake.....use it.
     
  23. LMAO!!!!:D;)
     
  24. I know the Lokar shifters have a fine threaded rod for fine tuning adjustments between gear positions also, they include a couple of different trans shift lever mounting tabs. Should be able to dial in positions fairly easy, just takes a little farting around with.
     
  25. evobuilder
    Joined: Aug 27, 2007
    Posts: 432

    evobuilder
    Member

    man.... this was a good thread to start.... I sure learned a thing or two.... like by simply eff'ing around with my Lokar threaded adjuster, park works perfectly now and that a car will roll around in any gear other than park (which in hind sight, makes perfect sense).
    Thx!
     
  26. Awesome!
     
  27. 40fordtudor
    Joined: Jan 3, 2010
    Posts: 2,503

    40fordtudor
    Member

    I struggled with this concept with my C4---very same condition. It took some getting used to, but it works fine, except as stated in OP post.
     

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