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TH400 combo's?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by **DONOTDELETE**, Feb 2, 2001.

    TH400 combo\'s?

    So what are the different years and combo's for TH400's? I have a 700R4 to a NP208 and was wondering if I could hook a TH400 to the NP208? I know they matched them up on a few years, but not sure what the spline counts are. I am looking at maybe going with a TH400 to my NP208 and then a NP205 until I can afford a doubler. Unless someone want to sell me a TH400 and NP205 combo !!

    [​IMG]<font color=red>BigBurb[​IMG]
    <font color=purple>IF YOU'RE SCARED, SAY YOU'RE SCARED !!
     
  1. ken

    ken 1/2 ton status

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    Re: TH400 combo\'s?

    Ya gotta find a TH400 first, then you need the adapter and the input shaft for the 208, since 400s have 32 splines, compared to the 700s 27 splines. This is between 1981 and 1988.

    ken
     
  2. HarryH3

    HarryH3 1 ton status Author

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    Re: TH400 combo\'s?

    Peek under a late 80's 3/4-ton 4WD Suburban. I know they came with Turbo 400's but I can't remember what t-case they had. I think they had either the 208 or 241. If you want to go to a 400/205 at some point anyway, I'd just start with that now and forget finding bits and pieces. The 400/205 combo came in 1-ton trucks for several years. (I'm sure someone in here can tell us exactly which years!) [​IMG]

    Mine came out of an '80 model, which has the dreaded rear slip jointed output for the driveshaft. (Which I've never had a problem with. Breaking the driveshaft would make it impossible to drive without spewing t-case lube out the back, but it's worked great so far).

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     
  3. turbo

    turbo 1/2 ton status

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    Re: TH400 combo\'s?

    All 1980 have the 205
    So any 3/4 ton burb or 3/4 or 1 ton turck from 1980 is a TH400 with a 205
    Starting in 81 the 208 came out so all 198- thru 1988 3/4 burbs are TH400 with the 208

    The 700R4 and Th350 are used in 1/2 tons with the 700R4 apearing in 82 with Th350 prior. These have smaller spline count then the 32 used in the Th400 from heavier turcks.

    Thus you 208 will not accept the TH400 32 spline output
     
  4. Re: TH400 combo\'s?

    Does this mean that all TH400's are the same? Shaft length and spline count, ect..?

    [​IMG]<font color=red>BigBurb[​IMG]
    <font color=purple>IF YOU'RE SCARED, SAY YOU'RE SCARED !!
     
  5. turbo

    turbo 1/2 ton status

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    Re: TH400 combo\'s?

    Some minor varience but all early 80's should work.
    Of course this only goes for 4wd TH400 as the 2wd is different output shaft
     
  6. titanic

    titanic 1/2 ton status

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    Re: TH400 combo\'s?

    The t-400 that was hook up to a 203,(like what you have to get for the Doubler setup), had a shorter output shaft than the t-400 that hooked up to a 205. You can change these out when/ if you rebuild the tranny but you have to find one first.

    <P ID="edit"><FONT SIZE=-1>Edited by titanic on 02/03/01 09:26 AM (server time).</FONT></P>
     
  7. ken

    ken 1/2 ton status

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    Re: TH400 combo\'s?

    I just got done swapping in a 1984 TH400 that had a 208 behind it into my '90 Sub with a 241. I had to swap the input gear of the 241 from its 700 versioned 27 spline to the 400 version 32 spline to allow it to adapt to the 241. Also, I used the 400-208 adapter to mount the 241. All in all it was a bolt in, AND I AM SO FRIGGING GLAD TO BE RID OF THE 700 OVERDRIVE!!!!!!!!!! Drove it 300 miles with the 400 tranny, 4.56 gears and 35" BFGs and still got 12 MPG!! All this in a one ton (Dana 60, 14 bolt) Suburban!!!

    ken
     

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