Tranny Wanted

Discussion in 'Parts Wanted' started by 83_k10, Oct 8, 2005.

  1. 83_k10

    83_k10 Active Member

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    I'm looking for a Turbo 350 or a 400 for my 83 K-10.something that can handle the long distance towing I need it for.
     
  2. BadDog

    BadDog TRC Staff Staff Member

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    Th400 is definitely kind of the 3spd towing transmissions, but there is more to it than that.

    K series would indicate 4WD, that means it could have one of several different transfer cases and that will make a difference in the transmission you run to match. The 400 had 3 different versions of output shafts, one for 203, another for 205, and a third for 208. Th350 had 203 and 205 versions, and can be adapted to 208, though AFAIK, they never came mated. There are also several different tcase/trans adapters of differing lengths and patterns including round or "figure 8" on the tcase side, and a 4 bolt (th350) or asymmetric 6 bolt (th400) on the trans side.

    Anyway, point is, depending on the tcase you have, you need a transmission to match, or a new mated pair, but that means probably changes to drive shafts, shifters, and so on... I often think GM hired a Ford engineer to work on those pieces. :rolleyes: And strangely enough, Ford, well known for changing bell bolt patterns on every different version of anything, and often mid year on identical parts, and many other things seemingly designed specifically to annoy the typical "enthusiast", actually got that part right having only one output shaft (and 31 spline at that!) across (most?) all versions. :doah:
     
  3. Mr. Beer/Cummins

    Mr. Beer/Cummins Well-Known Member

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    I have a th350, where are you located?
     
  4. 83_k10

    83_k10 Active Member

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    All i know about this truck is that it was originally a 305,somebody had a built up motor in it but yanked it out and that's when I came to find it for sale.It also originally had a 700 in it, but now has a 350,all I know about the transfer case is that it is magnesium,rather than cast.I am in Greencastle Indiana.how strong is the 350 and how much?
     
    Last edited: Oct 11, 2005
  5. Mr. Beer/Cummins

    Mr. Beer/Cummins Well-Known Member

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    How much weight do you plan on towing? I'm located in Louisiana, the price is $100. Very low miles, maybe 10,000 on it.
     
  6. 83_k10

    83_k10 Active Member

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    I bought it to tow impaired vehicles as I do repairs out of my garage,all are towed on a full trailer.I do not like Dollys.how strong is it?It is a 4wd trans with the reinforced case?
     
  7. BadDog

    BadDog TRC Staff Staff Member

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    That's probably a 208 case then, can't remember if the 203/205 output on the th350 fits the 208 or if it requires a different output, might want to check into that. I do know you can get a th400 that mates to a 208/241 from (roughly) 85-91 K/V series 1 tons and military CUCVs. But that will require changes to the length of your drive shafts.

    And the "reinforced case" is really just a heavier "lip" on the bell housing where a cast inspection cover bolts up with 6 3/8-18 bolts instead of a stamped sheet metal cover with screws. The cast cover does add to the strength of the bell housing when the braces are used to tie into the motor mounts, but the actual "bell" and the rest of the case are absolutely the same as a standard care transmission.

    As for a th350 holding up to towing, sure, it will hold up to moderate towing use. Main thing I would suggest is to add a VERY good stacked plate cooler to the trans line *before* it hits the radiator. Don't go cheap on this item, get a good one. I ran a 2WD 76 C10 with a 350 and th350 that I inherited from my Grandfather for about 8 years. I built a "Heavy Half" spring pack for it and hauled/towed fairly heavy with it on many occasions with no problems other than slight brake fade at times (I should have had a 3/4+ for some of the things I was doing, and you probably should too just for the brakes). But if you will be doing a lot of heavy towing, live in a hilly area, or otherwise will be working it hard, then I would seriously look into getting a th400.

    Problem is, th400 for a 4WD is a somewhat hard to find beast. I've got 2 of them (1 203 version and 1 205 version with matching cases and adapters) for my own use (2 K5s and a GM "truggy") but it can take a while to find one. Or you can get any old th400 with the Chevy bell and put the right output in it along with a rebuild. Or switch to a 2WD truck.

    Also, speaking of brakes (and more work/money), you can upgrade your K10 to a K20 by (for the most part) bolting on a set of 8 lug 3/4 ton axles. Probably get you better (lower) gears too if you look around. Lower gears will take a LOT of load of the transmission when towing. And that is yet another thing to look at. Being 4WD, you likely have larger tires, which effectively makes your gearing much higher, and in turn puts more load on your transmission.

    So I guess what I'm getting at in all this rambling is, it takes a whole package. Problems in gearing, brakes, tire size (for lateral stability, braking ability, and effect on final drive ratio), transmission strength, and engine torque curve are all going to factor in on whether the truck "works" for the application and lasts, or struggles and dies (hopefully not taking you or anyone else with it).
     
  8. Mr. Beer/Cummins

    Mr. Beer/Cummins Well-Known Member

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    well put waytogo
     
  9. big94GMC

    big94GMC Well-Known Member

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    I have a TH350 here in Pensacola for sale, bolted to an NP203, recent rebuild, strong. I want to get $450 for the whole setup. Don't know if you'd be interested, but if ya are....
     
  10. 83_k10

    83_k10 Active Member

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    Thank you all for the info responses and offers,but I am going to attempt my first rebuild.I have a damn good th350 that my Dad rebuilt but it is in an elcamino and he told me the weight od the transfer case on it would split the case in half he has seen it several times.(He was a tranny specialist for 40 years,but won't rebuild mine for me)He put it best when he told me this is a good time to learn.So I'm going to try it.I found out that this tranfer case is manufactured by "New Process Gear" for Chrysler products.So basically I have a Chrysler transfer case bolted on to a Chevy tranny :stir: .Interesting....
     
  11. BadDog

    BadDog TRC Staff Staff Member

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    New Process (often abreviated NP, as in NP205 or NP203) is now known as "New Venture" (as in NV4500).

    And I know this is the internet, and you don't know me from "Jack", and please don't take offense, but your father is wrong based on what I've seen. I've gone through several of both breeds and actually cut apart the cases, mic'ing the wall thickness and comparing them. I just tossed the remains of 2 of them out for "bulk pickup" today. Based on that, I can say for a fact that the only diff I could find in a 4WD case and a 2WD case (other than the inspection cover lip for "K cases) is the output shaft. Also, many 4WDs came *without* the "K case" heavy inspection cover and still survive with a heavy tcase hanging off the back to this day. In fact, I just bought another one that has seen HARD duty in a friend's K5 with a "doubler" (203 range box with a 205 behind it, VERY heavy) and it will replace the broken "K case" that is currently in my truggy. And as another data point, it is not uncommon for people to take 2WD th400s and install a 4WD output shaft (either 203 or 205 depending) so they can avoid looking for the hard to find "correct" Chevy th400 or to put a BOP in a 4x4.

    All that said, good luck on your first tranny rebuild.
     
  12. dieselgearhead

    dieselgearhead Member

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    Just to let you know, Pioneer products offers a retro fit kit for the 700R4 to TH400 for the 208 transfer case. It has an output shaft, tcase to trans adapter and a few shifter decals for diff model trks. I used this kit on an 86 1/2 t 4X4 sub that was a diesel and installed a 450hp 460ci BBchevy. The only bracing I had on the transfer case was the one from the rear of the tcase to the engine bellhousing bolt. The trans had a B&M street/strip shift kit in it and it would bark the hides goin into 2nd gear at 5500 RPM( ya a lot for a big block I know). I drove the snot out a it and it lasted for the 72000 miles I put on it and is still goin. Seen it the other day and it has 146000 on it and still goin. Sorry to express myself like this but there is a simple kit from pioneer trany products that will handle any abuse you can throw at it. Hope this helps and if your done with your project, disregard my rambling
     

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