TH350 issues

Discussion in 'The "Juice Box"' started by 71skylark3504v, Apr 29, 2012.

  1. 71skylark3504v

    71skylark3504v Goin' Fast In Luxury!

    The transmission in my truck is giving me problems. The 1 to 2 shift is normally very delayed and sometimes it will shift at the normal rpm. However, it will not do a 2 to 3 shift by itself at all. The only way it will do it is if I shift the transmission from N to D. Then 10 seconds later it will downshift again and I have to shift from N to D again. What should I check? Vacuum modulator is hooked up.
     
  2. DaWildcat

    DaWildcat Platinum Level Contributor

    Off the cuff, does the modulator hold a vacuum?

    When's the last time you did a fluid/filter change?

    Devon
     
  3. sean Buick 76

    sean Buick 76 Buick Nut

    I say vacuum leak
     
  4. 71skylark3504v

    71skylark3504v Goin' Fast In Luxury!

    I will check the modulator. How is it removed? Fluid and filter change has never been done by me. I already bought the stuff to do it though.

    This wouldn't be the governor would it?
     
  5. DaWildcat

    DaWildcat Platinum Level Contributor

    It has a hold-down bracket not too different than a distributor; 1/2" wrench will do it if I remember right.

    Doesn't sound like it.

    Devon
     
  6. staged70

    staged70 RIP

    Get a vaccum guage and see what you have. Modulators are cheap. make sure the line is there and not cracked. Is kick down cabe hooked up? try the simple stuff first.the
     
  7. 71skylark3504v

    71skylark3504v Goin' Fast In Luxury!

    Well, it was the vacuum modulator. Took it out and fluid poured out the vacuum nipple on its way to the trash can. Also did fluid and filter change, and failed for the third time to replace the shifter shaft seal.

    Last time I will ever drop a pan on a transmission! What a mess!:rant:
     
  8. 71skylark3504v

    71skylark3504v Goin' Fast In Luxury!

    Transmission still is acting up just like before. However, it acted fine when it was cold, then when the tranny got up to temp. the problems came back.

    What gives? Sounds like rebuild time.
     
  9. Sir Speedy

    Sir Speedy Well-Known Member

    Most likely cause is either the piston seals or seal rings in the high/reverse clutch drum. Yep, sounds like rebuild time to me.
     
  10. 71skylark3504v

    71skylark3504v Goin' Fast In Luxury!

    I put some Lucas Transmission Fix in it, and it's back to shifting great.
     
  11. sean Buick 76

    sean Buick 76 Buick Nut

    Great, now find another trans and have it rebuilt for when the bandaid fix fails...:TU:
     
  12. 71skylark3504v

    71skylark3504v Goin' Fast In Luxury!

    Yup, the problem came back. So what do I do? What any redneck would do with a beat up off-road truck, dump in another bottle of transmission fix. :laugh: Problem is still there, but it is tolerable on the highway and still runs great on the trails.

    Tranny shop wants $850 to pull and rebuild trans. Eventually I will let them do it but I don't want to spend that money right now.
     

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