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Can anyone help with a turbo 400 problem?

Discussion in 'The Garage' started by Trailblzn, Apr 29, 2002.

  1. Trailblzn

    Trailblzn Registered Member

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    I just put a turbo 400 in my blazer. It appears to be recently rebuilt, but it shifts hard into reverse and from 1st to 2nd and 2nd to 3rd. Does anyone know of any common causes and/or easy fixes for this. I would really appreciate any info. Thanks, Scott
     
  2. lt61173

    lt61173 1/2 ton status

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    does it have a shift kit. also check the modulator valve it may be bad
     
  3. Trailblzn

    Trailblzn Registered Member

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    I'm pretty sure it has a shift kit, I have had transmissions before with shift kits, but they never shifted this hard. The modulator valve looks new. I priced one and they are only $13 so it's probably worth a try.
     
  4. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    Does it drag out the shifts too? If so maybe you vac. source is weak?

    -Dan
     
  5. Trailblzn

    Trailblzn Registered Member

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    No, it seems to shift at the right speed, but it shifts so hard it jerks the whole truck.
     
  6. HarryH3

    HarryH3 1 ton status Author

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    Sounds like it has a shift kit that's set on "stun". /forums/images/icons/wink.gif If you pull out the modulator, very gently remove the piston that it presses against. See if there is a spring behind that piston. If not, see if your local tranny shop will donate one to you. Some shift kits have you remove that spring, which results in VERY hard shifting. You can also get different rate springs to put behind that piston to adjust the harshness of the shifts.
     
  7. Trailblzn

    Trailblzn Registered Member

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    Thanks for the shift kit info I will check it out tonight!
     
  8. Trailblzn

    Trailblzn Registered Member

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    Harry - There dosen't appear to be a spring behind the piston, when I pushed it in it didn't push back out. I tried pulling the piston out but it didn't want to come, do you have any secrets on getting it out. Thanks, Scott
     
  9. DesertDueler

    DesertDueler 1/2 ton status

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    Removing the spring is an old racers trick to getting them to shift really hard. It works great. Leave it that way. It will make the tranny last alot longer. I just rebuilt my tranny in my race car after 3 years or racing and 3 years before that on the street, and everything still looked great. I just did it to be safe since I dont want anything to break and keep me out of the race season.

    Dan
     
  10. HarryH3

    HarryH3 1 ton status Author

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    It was over 10 years ago when I messed with mine. /forums/images/icons/shocked.gif Seems that it slid right out though.
     

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