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  1. #1
    Sr. Apprentice
    Join Date
    Jul 2009
    Location
    Weatherford, TX
    Posts
    56

    Default Torque Convertor Not Locking Up 4l60e 95 K1500 sub

    Hey y'all, I've seen a few topics that address this in different ways but none with the same basic symptoms as mine...all shifts nice and firm, but absolutely no lockup.

    This is a used 4l60e with it's TC out of a mid 90's K1500 pickup. I just installed it as-is into my 95 K1500 Sub. All I did was replace front pump seal, change filter & fluid, & wash it off. Shifts great, but no lockup whatsoever.

    I checked all the electrical connections & read alot...so it looks like I need to plug up the scanner & make sure the PCM is sending a lockup command?

    And if it is, I need to replace the TCC Solenoid, right? Sounds easy enough...someone tell me if I'm wrong here... Please and thank you
    '95 1/2 ton Suburban 4wd 350, 140K, w/ tornado and k&n filter | everything else stock

    '89 1/2 ton Suburban 2wd 350, 200+K, completely stock except 31 x10.50 tires & 40 series flowmaster

    '85 1/2 ton Suburban 2wd 350, 250+K, burnt valve :lol: , edelbrock 50 carb, comp cam, silvolite pistons, HiPerf distributor, 18" glasspacks

  2. #2
    Sr. Apprentice
    Join Date
    Jul 2009
    Location
    Weatherford, TX
    Posts
    56

    Default

    Bumping this...upon further investigation:

    No transmission codes, no engine codes, PCM is sending Lockup command. Fluid level good, color nice & red & new smelling.

    Still great shifts...no lockup whatsoever. Help Please!!

    Any further thoughts?
    '95 1/2 ton Suburban 4wd 350, 140K, w/ tornado and k&n filter | everything else stock

    '89 1/2 ton Suburban 2wd 350, 200+K, completely stock except 31 x10.50 tires & 40 series flowmaster

    '85 1/2 ton Suburban 2wd 350, 250+K, burnt valve :lol: , edelbrock 50 carb, comp cam, silvolite pistons, HiPerf distributor, 18" glasspacks

  3. #3

    Default

    I'm drawing a blank here... Just replying so you don't start thinking that we are ignoring you! (plus a free bump-ola)
    "It went together didn't it? Well then there has to be a way to take it apart!" - Me.

    Check out my image gallery HERE.



    "The true measure of a man is how he treats someone who can do him absolutely no good." ~Samuel Johnson (1709-1784)

  4. #4
    Sr. Engineer
    Join Date
    Oct 2010
    Location
    Indianapolis, In
    Posts
    487

    Default

    How does one tell whether the TC has locked up or not? For sure, without guessing.
    2000 GMC YUKON SLT, 5.3L tow pkg, G80 rear/w 3.73 gear

  5. #5
    Sr. Apprentice
    Join Date
    Jul 2009
    Location
    Weatherford, TX
    Posts
    56

    Default

    Quote Originally Posted by dpeter View Post
    How does one tell whether the TC has locked up or not? For sure, without guessing.
    I can only speak to 700-R4 and 4L60E transmissions. But basically the process goes like this when it's working correctly:

    Starts in 1st gear, shifts to 2nd, shifts to 3rd, then lockup, then 4 (OD). It will feel like 4 separate shifts if your transmission is set up and working correctly.

    Ways to check if Converter is locked up:

    • When cruising at highway speed in 4 (OD), while you still have your foot on the gas, barely touch the brake pedal. The RPM's should jump up a few hundred. This is the converter un-locking. If RPM's don't go up, it's not locked up.
    • If you know you're in 4 (OD) and the RPM's go up without downshifting when you're climbing a hill, the converter is not locked up.
    • When it's locked up, your transmission should feel like a normal stick shift would, you can just "tell" the transmission is locked to the engine RPM, no torque converter slush/slip when climbing hills, accelerating slowly, etc.


    - - - Updated - - -

    I'm gonna replace the TCC solenoid and see where that gets me. Will update
    '95 1/2 ton Suburban 4wd 350, 140K, w/ tornado and k&n filter | everything else stock

    '89 1/2 ton Suburban 2wd 350, 200+K, completely stock except 31 x10.50 tires & 40 series flowmaster

    '85 1/2 ton Suburban 2wd 350, 250+K, burnt valve :lol: , edelbrock 50 carb, comp cam, silvolite pistons, HiPerf distributor, 18" glasspacks

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