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Transmission Problems

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by cityfarmer2, May 5, 2001.

  1. cityfarmer2

    cityfarmer2 Guest

    Guys being that I am on the other side of the planet need a good diagnois from those who will listen. My TH400 is slipping but only after startup. If I sit sometimes up to ten minutes the problem goes away and doesn't return until the next day. I have pulled the tranny pan no metal fluid looks ok just a little gray tone. Doesn't smell burnt. I traded for a used th400 but it is for a 1 ton longer output shaft. Anyone know how hard it is to adapt this to our Blazers. I have a NP208 and stock driveshafts for a 3/4 ton Military Blazer. Could it be a leak down on the torque converter? Thanks Gary.........
  2. mudhog

    mudhog THEGAME Staff Member Super Moderator

    Nov 6, 2000
    Likes Received:
    portland oregon
    sounds like you have bad seals as it only dose it when cold

    77blazer see it at<A target="_blank" HREF=http://community.webshots.com/user/ssmith6333>http://community.webshots.com/user/ssmith6333</A>[​IMG]
  3. cityfarmer2

    cityfarmer2 Guest

    Any Idea how hard of a job it is to replace those seals, does it require a complete rebuild. See I am still in Korea and the correct tools are hard to come by. I am a better than average skilled mech. and sure I could handle a rebuild but tooling is a problem.
  4. Ancient_4X4

    Ancient_4X4 Registered Member

    May 5, 2001
    Likes Received:
    ND, USA
    Mine was doing the exact same thing with the slipping and not shifting into gear right away when I started it, then after it had been driving it was fine. I checked the tranny dipstick and it showed full. I was worried so I when I took it in to have the front bearings replaced I asked them to look at the tranny. When I got it back my mechanic told me that it was 2 quarts low in transmission fluid. Doh! Now it works like new again.
  5. dyeager535

    dyeager535 1 ton status Premium Member

    Dec 13, 2000
    Likes Received:
    Roy WA
    the th400 is easy to rebuild. Its one of those "mightaswells" though..if you are in there, you may as well redo the clutches as well...seriously, you have to remove them to do the seals anyways. If you are above average skill, are creative, and have access to a press that will allow you to fit a pretty large drum/shaft under it (maybe 15" high??) you can do it. The absolute worst part IMO is getting the drums together..they have I believe 16 small, but high pressure, springs that need ot be compressed, and a press or the right tool is the ONLY way to do it.

    For instance (its been awhile) the output shaft. It has a drum on the end where the clutches sit. The shaft is a press fit, you don't want to remove it. So you have that thin, long output shaft, with a drum on teh end, that has to be compressed...if the press has a 1" hole in the center where the shaft can fit through, no problem...otherwise its a precarious balancing act, and it cost me, of course, one spring that I couldn't find. Since there were 16, I just removed the opposing spring as well and called it good. No problems.

    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
  6. cityfarmer2

    cityfarmer2 Guest

    Thanks for the info. I have ordered a rebuild kit and if I run into any problems I'll just get on the net and talk to all these good people at Colorado K-5. Thanks again......

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