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Auto Trans question

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by MikeH, Nov 27, 2001.

  1. MikeH

    MikeH Registered Member

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    Location:
    Monument, CO. USA
    Hello, having trouble with my Turbo350 trans. on my '71. Its a TCI Streetfighter with auto/manual valve body with a B&M shifter. Recently, I've noticed that in automatic mode, it is slipping and will not shift gears very well, I can rev it in Automatic mode and the engine will rev but the tranny is slipping. Fluid level/filters are all OK.

    However, in manual shift mode, all is working normally. No slippage or racing when I get on it... and when I shift all is normal. ??

    Any hints appreciated...
     
  2. ZZ4x4

    ZZ4x4 1/2 ton status

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    If it doesn't slip in manual mode, sounds like a valve body or vacuum modulator issue. The easiest to fix would be the vacuum modulator. It normally reduces shift harshness and if stuck in the activated position can cause slippage. Also if the valve body shift actuator pistons are blowing by due to a bad seal ring, the tranny may slip. These can be checked by dropping the pan. More serious issues could be a cracked seal on the front pump or loose pump bolts, but is more unlikely. Hope it helps. JT
     
  3. MikeH

    MikeH Registered Member

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    JT, thanks for the info, I suspected something like that may be the cause. The blazer is going into maintenance mode for a week or two soon for this and other work. I'll update this note when the solution is found....

    MH
     

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