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How to identify a TH350 "K" case?

Discussion in 'The Garage' started by BadDog, Mar 13, 2003.

  1. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    How to identify a TH350 \"K\" case?

    I've been looking for a TH350 "K" case (also called a HD case) to build a doubler behind (due to general shortage of TH400 203s). I'm not real happy about loosing the strength of my TH400, so I figure if I'm going TH350, I want the HD/"K" case.

    Problem is, it seems maybe I don't know how to ID the TH350 "K" case. I think K30guy or someone posted this a long time ago, but I can't find it now.

    I *thought* it had these characteristics.
    <ul type="square">
    [*]A visibly thicker and reinforced case. Hard to ID this without something to compare to beside it...
    [*]A "K" cast into the top of the main barrel of the case, behind the bell housing.
    [*]A 6 bolt cast inspection cover under the torque converter, rather than the 4 bolt stamped sheet metal version.
    [/list]

    So, am I confusing this with the TH400, or completely clueless. Can someone please give me a clue?
     
  2. Silver84k5

    Silver84k5 1/2 ton status

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    Re: How to identify a TH350 \"K\" case?

    you thought right........... ;P
     
  3. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Re: How to identify a TH350 \"K\" case?

    Thanks. But one of the guys I've been talking to has a case wtih a 6 bolt cover, but no "K". /forums/images/graemlins/confused.gif
     
  4. COCHEV

    COCHEV 1/2 ton status

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    Re: How to identify a TH350 \"K\" case?

    i have one in my garage. its pretty much gutted, but the valve body is still in it. never got around to rebuilding it.
     
  5. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Re: How to identify a TH350 \"K\" case?

    The big 'fawkin' "K" is cast into the bell housing part on the TH350. If it doesn't have the "K" the other features won't be there either...so the "K" is what to look for (plus it makes sorting through the pile faster...)

    Rene
     
  6. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Re: How to identify a TH350 \"K\" case?

    Not all stampings have the "K" on them. Some are known to have "HD" or another letter but can't remember what it is. I need to go out to the shed and see what that other letter is.

    The only best surfire way to tell is by the 6 bolts holding the dust cover on. These are actual bolts instead of screws that hold the 2wd thin metal covers.
     
  7. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    Re: How to identify a TH350 \"K\" case?

    [ QUOTE ]
    The big 'fawkin' "K" is cast into the bell housing part on the TH350. If it doesn't have the "K" the other features won't be there either...so the "K" is what to look for (plus it makes sorting through the pile faster...)

    Rene

    [/ QUOTE ]

    Rene, i hate to say this but ethier you are wrong or i am flat out BLIND. i was looking at my Th350 lastnight for russ. i cant not find a K anywhere on the case. BUT i do have 6 bolt holes. and the case is nice and thinck. thicker than i remember on a friends Th350.
    grant
     
  8. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Re: How to identify a TH350 \"K\" case?

    Wes, is the other letter "J", I'm not sure, but that sticks out in my head.

    As stated the HD cases will have 6 tapped holes for 3/8"(??) bolts and will use the cast aluminum cover with holes tapped for the motor strut rods.

    The 2WD or light duty cases have small holes tapped for screws that hold on a THIN stamped steel cover.
     
  9. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    Re: How to identify a TH350 \"K\" case?

    I know this is true for TH400's so I would assume it applies to TH350's as well...

    The HD cases can come with the thin cover BUT will have the undrilled bosses cast on the housing that would accept the thick cover. All you would need to do is drill the case and you can bolt the bigger cover on.
     
  10. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    Re: How to identify a TH350 \"K\" case?

    Just in case anybody was interested, I took some pics of an undrilled 400 case today and posted them on my Webshots page. Take a look in the "Parts Pictures" album.

    Webshots
     
  11. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Re: How to identify a TH350 \"K\" case?

    Cool, thanks. Until this thread, I had never run across that...
     
  12. Chief Brody

    Chief Brody Chief of Amity Police Premium Member GMOTM Winner

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    "K" case:

    K case.jpg
     
  13. MTBLAZER89

    MTBLAZER89 3/4 ton status GMOTM Winner

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    Holy old thread!!
     
  14. Chief Brody

    Chief Brody Chief of Amity Police Premium Member GMOTM Winner

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    Yep, old thread, but I am looking at transmissions and I didn't know about the "K" until I read this thread. Looks like I may have to have mine rebuilt since none of the ones I have looked at have a "K" or "HD"....
     
  15. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Take pics of the seating area where the dust cover sits. Show the thickness of the lips and the bolt holes, too.
     
  16. boz42

    boz42 1/2 ton status GMOTM Winner

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    I have seen more cases that had the thick 6 bolt mounting pads, & no letter stamp, than I have that had the letter in the bell.

    I always like finding the stamped "K" cases.
     
  17. Chief Brody

    Chief Brody Chief of Amity Police Premium Member GMOTM Winner

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    I would, but that picture isn't of my transmission :doah:

    I have't dropped mine yet.

    I don't know if I have a "K" on mine yet...and I haven't counted the dust cover holes yet. I am hoping that I do...but it's real hard to see that part of the bell housing with the transmission still in.
     
  18. diesel4me

    diesel4me 1 ton status Premium Member

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    Personally,I dont think that having a "K" case is a MUST...it's "desireable" but not something you HAVE to have either..my K2500 has a TH400 that came from a car or 2wd truck and doesn't have the cast cover or even tapped holes in the case for one,yet I have managed to plow with it for 7 years without issues,and the truck gets the crap kicked out of it every time I use it too--not my choice,ots the type of wet cement snow we get here..if the "regular" cases are so "weak",why are so many still in use today that have had no issues?...heavy duty IS nice,but not something many of us will ever need,really...in a way I feel its more for bragging rights than actual nesessity ,why most 4x4 enthusiasts want the "best"....
     
  19. JDNobodi

    JDNobodi 1/2 ton status Premium Member

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    Chief Brody, I doubt you would have a "K" case. It seems like an afterthought because a 73 I parted out, my 74, a spare th350/np203 which came from a 74, all came with non "K" cases.
    What I'm trying to say is, the "K" case came out during the mid to late seventies. Around the same time when GM went from the frame support to the support braces. The braces that run from transfer case to bellhousing, and the two braces that run from torque converter cover to the motor mounts.
     
  20. Cornfield creations

    Cornfield creations 1/2 ton status

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    Mine is a K case. Factory tranny. Has a super thick aluminum inspection cover. Support rod for that pale the the motor mounts, support rod from tranny to transfer. Super thick bellhousing. Everything that has been mentioned, and it's a 79.
     

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