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  • Some Tech advice please! Painless Wiring 700R/4 Transmission Torque Converter Lock-Up

    OK here's the exact word for word quote for this item in the 4wd catalog...

    "Now you can control the lockup converter on your overdrive transmission with your carbureted engine and not have to buy an expensive computer! With this easy to install Lock-Up Kit from Painless a vacuum controlled 4th gear pressure switch/lockup solenoid combination controls the lockup. Fits any GM 700R/4 transmission."

    OK kids, what exactly does that mean? I know they have torque converter lockup units that allow a guy to lock up the converter in any gear any time. I've heard that they'll even stall at a stop light if it's locked just like a manual would if you forgot to push in the clutch. Would the above unit do that if it was locked? It'd be great if it'd lock in any gear any time. If it does, what about being able to push start the vehicle? That is the main thing I miss about not having a manual.
    Last edited by BigSkyGuy; 03-23-2006, 08:09 AM.

  • #2
    To a point what youÂ’re thinking is right. But it doesn't quite work like that. It requires hydraulic pressure to lock the converter up, so you still have to go fast enough to build up pressure to bump start it. General Idea, 40+ mph and you can bump start an auto!

    All it takes is a switch sending 12V to the tranny to energize the solenoid and lock up the converter. The only thing the kits have is a vacuum switch that automatically kicks it on and off.

    I burnt up a tranny once when I swapped a 700r4 in and used a toggle switch to activate the lockup, ended up burning out the lockup clutch bands by having it locked when it shouldn't have been. It trashed the transmission and torque converter.


    • #3
      Pretty sure those kits have a vacuum "switch" that controls the lockup off engine vacuum.


      • #4
        Yes, the kits have a vacuum/electric switch to disable the TCC under acceleration and when the engine is under heavy load (low vacuum). As mentioned the TCC cannot be used to push start an auto, but it does help with fuel economy and heat buildup by "locking" the torque converter when cruising at highway speed.

        Not to undermine anyone's sales pitch, but you can find the same vacuum switch on an older S-10 blazer with the 700-R4. 1985 and earlier Fedral emmisions. These units had a TCC but did not have a computer. The switch is usually mounted on one of the inner fenders.