Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Torque Convertor Will not Unlock

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Blazer_Boy, Oct 22, 2001.

  1. Blazer_Boy

    Blazer_Boy 1/2 ton status

    Joined:
    Dec 16, 2000
    Posts:
    1,669
    Likes Received:
    0
    Location:
    Sioux City, IA, USA
    '81 w/TH350c (low rpms after third shift, and shudders under load until up to highway speed)

    I'm really sorry for constantly posting about my shuddering problems, but I think I have found the problem. After consulting sources more knowledgeable then me I've come to the conclusion that the torque convertor is locked up. I mean it makes sense, low RPMS early in third gear and shuddering from clutches having too low of RPMs against them after the shift.

    The convertor is brand new and was working fine for a week after the overhaul. I've tried unplugging the wiring, but to no avail. Should I dump some Seafoam tranny treatment in, or is it BFH time. I really dont wanna slide the tranny back and replace the convertor, but if I can get another under warranty, might as well.

    Thanks,
    Jon

    <a target="_blank" href=http://www.geocities.com/bigkern76>http://www.geocities.com/bigkern76</a>
     
  2. Thumper

    Thumper 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    1,582
    Likes Received:
    0
    Location:
    Alberta Canada
    I just had a similar problem with my TH400. At take off from a stop, it felt like it was running in 3rd gear already, although it would shift twice. After 30km/h, it would work fine. The explanation I got was that the stator gear in the converter that slides over the tranny input shaft is made of aluminum, and the tranny input shaft is steel. Sometimes, the steel shaft will strip the teeth off the aluminum stator, and that wont allow the converter to unlock, because the stator will not turn with the shaft... or sumthin like that.
    Long story short, Im not sure what you were planning the BFH to do, and I really doubt that the additive will help ya if its the same prob as mine. It sounds to me like its time to pick up a new one...

    Mike


    <font color=blue>Thumper
    85 Fullsize Jimmy
    [​IMG]
    <font color=red>Aint Skeered!! </font color=red>
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,980
    Likes Received:
    189
    Location:
    Roy WA
    If you unplugged it, and nothing changed, it more than likely is NOT the torque converter solenoid or clutch. If you disconnect it, it will NOT lock the converter, nor will the converter clutch itself have any effect on operation. Stranger things have happened I suppose, but if the TCC was truly locked up all the time, you wouldn't be able to come to a complete stop without the engine dying.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  4. ftn96

    ftn96 1/2 ton status

    Joined:
    Sep 26, 2000
    Posts:
    3,238
    Likes Received:
    0
    Location:
    Nashville Tn
    I thought 400's didn't come in the lock up fashion? Im probably wrong again.

    Surgeon General's Warning:
    Viagra and steroids may be harmful to your spouse![​IMG]
    <a target="_blank" href=http://www.nashvillek5.freeservers.com>www.nashvillek5.freeservers.com</a>
     
  5. Blazer_Boy

    Blazer_Boy 1/2 ton status

    Joined:
    Dec 16, 2000
    Posts:
    1,669
    Likes Received:
    0
    Location:
    Sioux City, IA, USA
    Hmmm, it sounds like its time to lodge a bitch complaint at the rebuild guy.

    ...Just kidding about the BFH, its the mechanic's cure-all, lol [​IMG]
     
  6. Blazer_Boy

    Blazer_Boy 1/2 ton status

    Joined:
    Dec 16, 2000
    Posts:
    1,669
    Likes Received:
    0
    Location:
    Sioux City, IA, USA
    OK, stupid relization time here. I changed the vacuum modulator about a week after getting the tranny in. I figured, what the heck, don't wanna any problems. Well about three days after doing that all this crap started. Could it possible that I have a bum modulator and it is causing the third shift too soon. It goes through the gears about as fast at my 700r4 does through 1-3.

    <a target="_blank" href=http://www.geocities.com/bigkern76>http://www.geocities.com/bigkern76</a>
     
  7. 84_Chevy_K10

    84_Chevy_K10 Banned

    Joined:
    May 30, 2001
    Posts:
    17,669
    Likes Received:
    0
    Location:
    IL, USA
    Are you sure the vacuum switch is still good?

    Try cruising down the road while depressing the brake pedal just enough to actuate the rear brake lights. The TCC should unlock.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  8. Blazer_Boy

    Blazer_Boy 1/2 ton status

    Joined:
    Dec 16, 2000
    Posts:
    1,669
    Likes Received:
    0
    Location:
    Sioux City, IA, USA
    I tried driving it around with the switch unplugged but never tried taping the brakes. I'm crazy enough that I unplugged the line to it and started sucking on it. Gas fumes didn't taste good but I did hear the switch click and when i let go it didn't release right away so the check is working too.

    I guess I'm taking shots in the dark here and wasting everyone's time but this has me stumped. The guy that overhauled the thing never seems to see fit to answer his phone or return my message and I get wierd or blank looks when ask other people whats wrong.

    <a target="_blank" href=http://www.geocities.com/bigkern76>http://www.geocities.com/bigkern76</a>
     

Share This Page