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GRIM...Help with TH350/NP205 ??

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Leadfoot, Aug 30, 2001.

  1. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Grim or anyone......

    Recently there was a post on the TH350/NP205 combo. I said it was rare due to what I have heard and been through (trying to find one). But I was told this by a few members:
    "Early 70's GMC rigs with the TH 350 all used the NP 205"
    and
    "A zillion '69 - '72 GM trucks had TH350/NP205 combo"
    I read your (GRIM) recent post about them being quite rare (72 and 80 only with it as a special option in 73-79 only) and was wondering who was correct??
    Can you shed any light please.
    Also Stephen stated: "You can use ANY TH350 version 205, we haven't seen any difference in the adapters, other than the early versions use a bearing in the adapter which is nice to have but far from essential"
    If I were to find an older version adaptor (72'ish) to replace mine (1980), is the "drive sleeve" different (the female adaptor that connects the tranny output splines to the transfercase input splines), and what is this bearing he speaks of.

    Thanks in advance.

    See my rig at <a target="_blank" href=http://coloradok5.com/gallery/Leadfoot>http://coloradok5.com/gallery/Leadfoot</a>
     
  2. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Look at it this way. 69-72 are 30 years old now. NOT many on the road. Tons of people had problems with the 203 in the 70's and most of the 1/2 (so TH350 equipped) 4x4's with Auto trannys the 203 was the default case. So the 205's in the yards that fit the TH350 were snapped up pretty quick to replace blown 203's.
    The last time there was a bunch of 205's that fit the TH350 was 1980. The 80's case was a slip yoke so less desirable for what we do. SO in 13 years we had millions of trucks built. The only heavy usage of TH350's was about 2 year. 72 and 80. Many of the 69-71's got Dana 20 cases. If it was a base model truck it got the Saginaw 3 speed and a Dana 20 through 72. The 205 behind the TH350 strated replacing the 20 around 70 from what I have read. GM had a lot of 20's around and several plants were installing them behind TH350's through 71. Lots of those trucks were 2wd so no case at all.
    80's was the last year of that body before they changed the front clip in 81 and started phasing in the 700r4 and 208. Whenever there is about to be a body change sales drop so 80 was not a big sales year and it was around the gas crunch when people were not buying trucks. There are only a few 80's owned by members here. There is probably double the number of 79's than 80's I only see a 80 truck of any style on vary rare ocassions. Most of the time It's BigJBears. Yet I pass lates 70's almost daily.
    A TH350 205 is rare when you look at the numbers that way. It's as rare as a 2wd Blazer. You can pick up 203's all day for around $100. A 205 being sold by somebody who knows what they got and how rare it is are listing for as much as $500 and they are getting it.
    If you have a 80 slip yoke case you can make it a fixed yoke by swapping a fixed yoke off a early case. I don't think it matters if it was a 205 for a 465 (most common 205). What might matter is if it came off a 1 ton since they run a larger yoke and that might be something you want if your running a 14bolt rear.

    It's not my damn planet monkey boy!
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    79 Chevy Blazer, Her's
    70 Chevy Burb
    Grim-Reaper
     
  3. californiak5

    californiak5 1/2 ton status

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    Now that's some good history to know. Thanks Grim.

    See Ya,
    Keith

    [​IMG] <font color=green>Born to Drive My K5</font color=green> [​IMG]

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  4. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Thank you for the info.
    Just wondering about the second part (as far as differences between the 72 and 80 adaptors). Stephen mentioned something about the 72 using a bearing. My 80 350/205 adaptor did not use a bearing (just a drivesleeve with two seals), and just wondering if I can't find an 80 adaptor but do find a 72 adaptor, if I need to use it's drivesleeve or if mine will do. Thanks again.

    See my rig at <a target="_blank" href=http://coloradok5.com/gallery/Leadfoot>http://coloradok5.com/gallery/Leadfoot</a>
     
  5. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    That I'm not sure about. Stephen is the man when it comes to the case and bearings. Might want to pop into the ORD board and post the question or look and see if that has been answered.

    It's not my damn planet monkey boy!
    <a target="_blank" href=http://communities.msn.com/OffroadK5s>communities.msn.com/OffroadK5s</a>
    75 Jimmy, Dollar
    79 Chevy Blazer, Her's
    70 Chevy Burb
    Grim-Reaper
     
  6. mike reeh

    mike reeh 1/2 ton status

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    wow grim, that is some really good information.. I learned a lot

    and I thought I was crazy for thinking 80' trucks were rare.. they ARE.. and you are exactly right that late 70's trucks are dime-a-dozen. good call.

    mike
     

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