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TH475?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Rolled, Dec 7, 2002.

  1. Rolled

    Rolled 1/2 ton status

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    I am looking for a turbo 400 to put in my Blazer. Durring my search I have seen references to the TH475. I guess this is a heavy duty version of the 400. Is that true? Did these come in Blazers?

    Also, can anybody tell me what makes it more Heavy-Duty and can a regular 400 be converted to the 475?
     
  2. Swanson52

    Swanson52 1/2 ton status

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    The TH475 is stronger because the planetary gears are straight-cut. You could find one in a motorhome, I think.
     
  3. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Swanson hit the nail on the head. /forums/images/graemlins/thumb.gif
     
  4. Rolled

    Rolled 1/2 ton status

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    Thanks guys /forums/images/graemlins/grin.gif
     
  5. morphed86k10

    morphed86k10 1/2 ton status

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    how would one identify if it was a 475 instead of a 400? I know my tranny is out of a motorhome, but I was told it is a 400. Any way to tell by the exterior?
     
  6. thatK30guy

    thatK30guy 1 ton status Premium Member

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    No way to tell the differences unless you tore it down to inspect the planetary gears.

    400 and 475 are the exact same tranny except for the planetary's. The share the same housing.

    One thing about the motorhome housings...they are almost a 100% guarantee that they are the 4 screw, thin dust cover, non K-case housings.

    If you were to get one built, I would ask for the 475 gears built into a 6 bolt dust cover K-case housing. /forums/images/graemlins/thumb.gif
     
  7. morphed86k10

    morphed86k10 1/2 ton status

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    would the gears sound differerently because of the straight cut? My tranny has a bit of a whine
    in first, I don't know if thats normal or not as its the first auto I've owned. Any ideas on that
    or is it normal?
    Ane what are you refering to about the "k-case"?
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    I think whine in first is inherent in all GM trannies, manual or auto, at least ones I've had. (TH400, 200-4R, SM465) Not sure of other makes, but perhaps first is the "strongest" gear (and thus different tooth angle on the gears). It would make sense, trying to get a tow-rig or heavy vehicle moving is harder than keeping it moving.
     
  9. thatK30guy

    thatK30guy 1 ton status Premium Member

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    K-case is the 4wd version tranny. It uses a 6 bolt dust cover instead of 4 screws like the 2wd version does. Most 4wd trannies have a deep pan.
     

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