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K-Case hoax?

Discussion in 'The Garage' started by BadDog, Oct 5, 2004.

  1. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Ok, I've always heard that the K-Case autos were heavier than the "standard" variety. Everyone seems to agree that the bell housing is thicker, and some claim that other parts of the case are also heavier. However, I have cut the bell housings off of a "standard" and a "K" case now and I can find no difference. They both mic just below 0.150, bolt bosses are the same, etc. In short, I can find no difference at all... Am I missing something? Does anyone know *specifically* what the differences are?
     
  2. wayne

    wayne 3/4 ton status

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    I have checked them out side by side and could not tell any difference. That's why I don't have a K case in mine.
     
  3. jac6695

    jac6695 1/2 ton status

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    I always thought on the TH400 and 350 that the bolts for the converter cover are smaller on the car cases. I do know for a fact that on 4L60E's, my Caprice case looked as thick as the K case I used, but the upper two bolts of the cover are not there (only 4 of them), but used the same size bolt.
     
  4. funkycold

    funkycold 1/2 ton status

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    I have had both in my sub and the only thing that I was able to notice is the inspection cover is different as the K case has the bolt holes for the strut rods to the engine.
     
  5. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

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    From what i understand the K case is the one that has the heavy aluminum bolt on inspection cover and the other is the tin screw on cover. Other than that I agree there is no difference. Talking to a professional tranny guy there are small differences but nothing that warrants searching for one over the other. I personally like the bolt on aluminum inspection cover.
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    Is K-case supposed to be 4wd only, or all truck applications?

    That K could very well just identify cases that have the bosses for the strut rods, as the part number for the case itself would be diffrent.

    Just speculating. If the case mics the same everywhere, then it would appear K is indicative of something other than thickness.
     
  7. mudjunkie 82

    mudjunkie 82 1 ton status GMOTM Winner

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    Could the metal contain some type of Alloy????
     
  8. wayne

    wayne 3/4 ton status

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    I have to look under mine, but I think the bosses are cast in to the inspection cover not the case. My cover was not on the trans when I got it so I can't really say wether it is from a K case or not.
     
  9. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Sorry, wasn't clear on that point. Yes, the K-case converter cover is definitely different being cast instead of stamped. And the case has heavy bosses (tapped or not) for 1/4-20 bolts used to mount the cast cover rather than the tin version. But I was under the impression that the case itself was stronger from more than just the converter cover with its mounts for the struts. /forums/images/graemlins/dunno.gif
     
  10. down4thakrown

    down4thakrown 1/2 ton status Premium Member GMOTM Winner

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    i thought k case meantit came in a k5,k10,k20 pretty much a 4x4 case???? /forums/images/graemlins/dunno.gif
     
  11. 84_Chevy_K10

    84_Chevy_K10 Banned

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    My 2wd '87 R/C 30 has "HD" cast into the bellhousing of its TH 400. It is certainly heavier/thicker than any normal TH 400 case I've ever seen.
     
  12. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    My 700R4 K-case is most definately thicker in the bell housing area and it is drilled and tapped for (6) 3/8" x 16 bolts not (4) 1/4" x 20 or (4) sheet metal screws. K cases were used in any truck 2wd or 4wd AFAIK.

    In the past i also had TH350 and TH400 K cases and they too were thicker in the bell housing area with the same bolt holes.
     
  13. thatK30guy

    thatK30guy 1 ton status Premium Member

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    I always believed the "K" case was "thicker" or "stronger" not in the overall housing but rather the mounting flange where the dust cover bolts onto. If you look at it compared to the standard housing, you will see the flange is thicker than the type that uses the thin 4 bolt dust cover. This was my only belief of the whole thing. /forums/images/graemlins/thinking.gif
     
  14. k20

    k20 3/4 ton status

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    well my highly scientific testing proved that when u hit them both lightly w. a hammer, in the same spot, they sound different, thus teh determination can be made that they are different, in some way, shape, or form.
     
  15. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    [ QUOTE ]
    i thought k case meantit came in a k5,k10,k20 pretty much a 4x4 case????

    [/ QUOTE ]
    It does, but they are supposed to be stronger in more ways than just a heavier converter cover. Or so the common "wisdom" states. I just can't find any other differences.

    [ QUOTE ]
    It is certainly heavier/thicker than any normal TH 400 case I've ever seen.

    [/ QUOTE ]
    I don't have an HD case to compare with, and it may be different between 400 and 350. But are you sure your not just basing that on the mounting flange for the cover? As I said earlier, that area is definitely heavier in the K case, but nothing else that I can find is different.

    [ QUOTE ]
    (6) 3/8" x 16 bolts not (4) 1/4" x 20

    [/ QUOTE ]
    Oops! /forums/images/graemlins/blush.gif Sorry for the brain dead data. 1/4-20 would be silly and I know better having rounded up bolts for mine before I found the crack, not sure where my brain was when I posted that. /forums/images/graemlins/doah.gif This post has not exactly been my best effort at being clear or accurate. <sigh> I guess I should take more time instead of making a quick post.

    [ QUOTE ]
    I always believed the "K" case was "thicker" or "stronger" not in the overall housing but rather the mounting flange where the dust cover bolts onto.

    [/ QUOTE ]
    That appears to be accurate. I was just under the impression, and have been told by more than one source over many years, that the bell housing wall was also thicker by some amount. It made sense so I never bothered to measure it. The I cut the bell off a standard and a k-case only to find that they are practically identical. If I had known that the ONLY difference was the mounting flange and cover, I would not have been so stuck on finding a K-case. I'm sure it makes a difference, but it's certainly not what I thought...

    [ QUOTE ]
    well my highly scientific testing proved that when u hit them both lightly w. a hammer, in the same spot, they sound different, thus teh determination can be made that they are different, in some way, shape, or form

    [/ QUOTE ]
    Other than the mounting lip, (which I suppose *could* make a difference in the sound /forums/images/graemlins/dunno.gif) good luck in finding that difference. I've actually cut my case up so that I have access to measure things accurately that are usually not accessible, and I can find no difference except the cover mounting flange...

    Anyway, my purpose in making this post was to find out if anyone *knows* about some other significant difference that I have not found. Yes, it's clear that the mounting flange is a bit heavier, but is there any other difference that anyone can point to that will make the K-case stronger?
     
  16. dyeager535

    dyeager535 1 ton status Premium Member

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    Old post, I know, but anyone have a link or pic of a "confirmed" 2wd housing?

    I just can't recall the ribs for output shaft "support" shown in this picture:

    [​IMG]
     
  17. k20

    k20 3/4 ton status

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    I got one sitting out in my backyard, 5 mins and ill go look.


    EDIT: Yeh its got the ribs on it, batteries are dead in my dig camera or I would take a pic of it.
     
  18. dyeager535

    dyeager535 1 ton status Premium Member

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    Dang, thought we had something there for a sec. :) TH400 only auto tranny with those ribs then?
     
  19. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    Take a look in my Webshots page (see sig) under the Parts Pics album. I have a pic of an undrilled HD case from a 4.3 V6 Astro van.
     
  20. R72K5

    R72K5 Banned

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    LOL @ K20 and his scientific testing haha thats great stuff :thumb: !

    :D

    but it does show that either thickness or alloy is different, or the sound would be same or really super close to it from one to the other with the hammer tap test.


    technically..


    only ppl that know for sure are those who designed these parts for GM back then, and no one here knows any of them, so we may never know for sure


    heh,

    we can only presume/opinionate otherwise,
     

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