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Tranny problems

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Stylzz, Sep 9, 2002.

  1. Stylzz

    Stylzz Registered Member

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    I have a 80 k5 with a 350-205 combination. My tranny does some wierd stuff. First, sometimes it takes forever for it to go into gear. I think this is from low fluid but I was wondering if anything else could cause it. Second, I have fluid leaking from my tranny to t-case is it just the seal or is it a bigger problem. And third, this is the real wierd thing, sometimes when I am accelerating and only giving it a little power and it gets into third I'll be going along and all of a sudden my rpms will drop by like 800. It almost feals like it is shifting into another gear but way too soon. If I nail it she will pick back up and start pulling like normal. If anyone knows what causes this stuff please help. Thanks.
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    Check fluid. If its low, it can take awhile to go into gear. More likely, the internal seals are worn, and leaking, so take more time to build pressure.


    You gotta find out where the fluid is coming from, exactly. If its a crack, you'll have to replace it. More likely its just the "paper" gaskets between the t-case and tranny that I'm assuming were used in your application.

    The "shift" you are feeling I'm betting is because you have a TH350C tranny, and the "shift" you are feeling is the lock up torque converter. Nothing wrong with that, although people say the TH350C is weaker. Not sure how, and not saying it isn't, but the locking torque converter *shouldn't* weaken the thing up so much to give it the reputation it has. Better mileage and lower engine RPM's at cruise are good things. You'll have a wiring plug on the drivers side of the tranny I'm guessing, (and you can trace) that is tied in with a vacuum switch in the engine bay, and your brake pedal switch.
     
  3. Stylzz

    Stylzz Registered Member

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    Thanks for the info. How much of a pain is it to change that seal? should I do it myself or have it done?
     
  4. Calclips

    Calclips 1/2 ton status

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    To change the seal your going to have to split the tranny/transfercase. You'll have to remove the front and rear driveshafts, support the rear of the tranny with a jack, get another jack and support the crossmember/tcase. Then you'll pull the bolts out of the crossmember and the adapter plate that mates the two together and pull the transfercase towards the rear of the truck (be careful, may be unbalanced and want to fall) then all you have to do is clean the sealing surfaces and get a new seal. Slap it all back together and tighten the bolts back to spec. It isn't too bad of a job if you've got a buddy to help out and a couple of hours to do it in. A haynes manual might be a good idea to have around if you've never done this before, it will have the torque specs for the bolts and pictures of what needs to be done.
     

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