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Tranny troubles not so troubling

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by NewK5Guy, Apr 19, 2001.

  1. NewK5Guy

    NewK5Guy 1/2 ton status

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    Since my last post, I've taken all your info to heart. A little more attention payed to the ol' 700 has showed that the tranny shudder is definately due to excess heat. The harder I push it, the hotter it gets, the more it shudders. I checked with my buds over at the diesel page and they said that the diesel 700 and the gas 700 do indeed have the same bellhousing bolt pattern, the only difference being the output shaft and tailhousing. So, should I need another, another shouldn't be as hard to find as I thought.
    Recently, we had a cold snap here in VA. I actually had frost on my windshield this morning(which was way cool!! Cause I got to use my defroster for the first time since I fixed the vacuum system). Since the beginning of the cold snap, the tranny has been decidedly tight, much tighter than when we had the hot snap(in the 80's for highs). So there's that observation.
    The other thing I wanted to bring up in the ongoing diagnosis is about someone mentioning does the converter unlock when you press the pedal? I tried that. Yes, it does. Every time. Just a light press and the tranny unlocks, but it won't stay. A light touch of the brake pedal will unlock the tranny, but it will settle right back into lockup unless I lightly depress the pedal further, even if I have began depressing the gas pedal further. I understand that that info should tell the more experienced here something very valuable. Please, share.

    One more thing...and don't take this wrong...please stop telling me to go to the diesel page and consult them. If you'd check my profile, you'd see I'm already a member. I post here for 2 reasons: 1-I have ALREADY consulted the diesel page and 2- this site gets soooooooo much more traffic I'm guarenteed an answer usually in the same day.
     
  2. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Hey dude, post all yer Q's here. Never mind them Diesel boys...[​IMG]

    Thought you might like to see a different response...[​IMG]

    Rene (just don't ask me about 700's [​IMG])

    [​IMG]<A target="_blank" HREF=http://jules.coloradok5.com>http://jules.coloradok5.com</A>
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    The switch for the TCC unlock I *believe* is the same one for the cruise control. Not sure if they ever went to one unified switch for all three (cruise, TCC, and brakes) but some used two switches, one with a "T" to run two things off of...I would assume the actual brake light switch, for safety(?) may have stayed seperate.

    In any case, after all that confusing info, it might just be that the switch needs to pulled further out of the bracket, so it does not stay "connected' to the brake pedal as long. You would probably have a similar problem with the cruise control if this is the case.

    Again, this is without looking at my wiring diagrams.

    The switches are typically white, and are semi-easily pushed further in or out, to adjust the "time" that they are disengaged. Easily seen if you look under the dash above the brake pedal.

    Dorian
    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>
     
  4. Blue85

    Blue85 Troll Premium Member

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    Your lockup switch is seperate from your brake/cruise switch. If it unlocks when you press the pedal, the switch is working correctly, but it sounds like it could help to adjust it a little bit towards you. It is easy to find, just take off the little rectangle of metal dash directly below the column and look up at the bracket in front of the brake pedal and you will see the switches. The one you want is white with a two wire connector going into it. The connector will have a locking clip on both sides of it. You will see how to adjust it when you get in there. If you leave this connector disconnected, the tranny will never lock up. I had trouble with that switch once, so I took it apart and rebuilt it. It's really pretty simple. Usually the problem is that it stops making contact and then you never lock, but it's possible that yours is breaking the contact as the plunger first moves back but then the leaves relax back and touch again. I don't know, you'll have to look at it.

    That switch has a vent for a vacuum signal that I never investigated. I would like to know what it's for if anybody knows.

    As for relocking while the brake is depressed, are you still on the gas pedal or is the tranny just "clutching out" to coast?

    <font color=green>"MAN THOUGHT HURT BUT SLIGHTLY DEAD" --Providence (R.I.) Journal</font color=green>
     
  5. NewK5Guy

    NewK5Guy 1/2 ton status

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    Thanks for the info. I'll look for that switch this weekend while I'm changing the oil.
    I can answer the vacuum question. The vacuum switch you see connected to the brake pedal is a vacuum dump that automatically turns off the cruise when you hit the brakes. letting off the brake then closes the switch and vacuum resumes building allowing you to resume use of cruise.
    As for relocking, I don't understand your term "clutching out". Here's what happens. I'm at steady cruise. I begin a gradual incline. I begin to lose speed. If I slightly press the brake pedal, the converter will unlock, then relock almost immediately thereafter. Even if I depress the gas pedal just a bit to try to gain some revs, it will still relock almost immediately. I will say that OCCASIONALLY(as in maybe 4 times in the 3 months I've had the truck), the tranny has unlocked as it should have. The most recent time was yesterday(Wed). It worked ok all by itself.
    So you say I need to move the switch in towards the pedal? Is that what you mean by "towards you"? How will adjusting this switch help the converter to unlock when it's supposed to?
     

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