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Turbo 350 trans trouble

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by slider, Feb 15, 2002.

  1. slider

    slider 1/2 ton status

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    I have a 80 GMC K15 pickup, 350, 375 H.P. turbo 350 transmission with a shift improver kit installed and 456 gears. I pull a 6000 lb. 27 foot travel trailer often at least once a month. The trans has an external filter and cooler. I have noticed on hard acceleration the 1 to 2 shifts are getting longer, used to shift right now, 2 to 3 are ok. I change the fluid once a year and it looks great, little or no junk in the pan. I was told that my kick down cable was out of adjustment and to try that and see if it helped. I still have the same problem. Manual shift its great. Any tranny experts have a idea what is going bad? Thanks for the inputs
     
  2. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    what kind of shift kit did you use and how many miles on it. also, what stage did you install?
    Grant

    1974 Chevy Blazer Cheyanne. but it is on 33's now, with saggy old springs. i am in Yuma Arizona if ya got any parts for me.
     
  3. slider

    slider 1/2 ton status

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    It is shift improver kit I think transadapt. It was installed when the trans was rebuilt in 1995 along with a fully welded converter. It might have 30,000 miles on it,
     
  4. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    i have had bad licu with TH350 and more than like 25k miles on them. except for transgo. i like the stage 1 kit on a 4x4 and the stage 2 on a car of any type.
    also might want to change the fluid on it more than once a year. maybe 2 times a year.
    Grant

    1974 Chevy Blazer Cheyanne. but it is on 33's now, with saggy old springs. i am in Yuma Arizona if ya got any parts for me.
     
  5. slider

    slider 1/2 ton status

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    tttt. Need help
     
  6. mnstr_fx

    mnstr_fx Registered Member

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    Just an opinion, but it sounds like your piston seals are starting to go. It could be something with the shift kit, but it sounds more like piston seals / valvebody leaking.

    76-82 Chevy Pickup / Blazer - K5-K10-K30
    90' TBI
    TH 400
    203 / 205 Doubler
    Dana 60, Corp 14 - 4.88'd - Detroit Locked
     

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