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700R4 lockup

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themoose:
Jef

I often see the question asked about whether or not running a 700 without the lockup functioning will cause damage. Most would answer a definite Yes but Performance Automotive Transmission Center has a statement on their web site that says the following.


--- Quote ---If you have a 1982-83-84 car or truck never drive it with the wires on the side of the transmission unplugged. This will overheat the transmission on a long trip. On a 1985 or later it is O K to have the wires unplugged, because of a design change made in late 1984. The only part of this transmission that is electronic is the torque converter lockup. You will still have all four speeds with the wires unplugged. 
--- End quote ---

Is this a correct statement and if so what changes were made that would eliminate the need for TC lockup?

Moose 

Senior31:
Moose,

       This is a good question.  If you don't mind I would like to add to the question.  Is there a way to check to know if your TC is locking up?  I purchased a 700r4 from TCI when I built my '35 and have had a number of issues with it.  I purchased a lock up kit with it, but a TCI rep said that it was already installed in the transmission so I returned it.  I have also had issues with the shift points.  I ended up purchasing a Bowler Tru-Shift kit and it helped, but I think it was heat related.  So, I installed a tranny cooler and it helped a bunch.  I still am not sure it is working correctly.  So, not to high jack Moose's question, but I would like to know if there is a test for this issue.  Any information would be helpful!

EDNY:
From the top of my head, I have a mini 12v LED on my dash, it has constant 12v (fused) via my brake pedal switch (ie foot off pedal LED & Tranny solenoid get power via purple wire).

I tapped into the light blue wire coming from the 700R4 to my ECM, the blue wire supplies the ground to the trans via the ECM (lock up) and -now- my LED.

Driving without brake pedal depressed both the tranny & LED have 12v (purple wire), the ECM determines lockup by sending ground to the tranny solenoid (& my LED) via the blue wire.

Stepping on the brake pedal opens the power circuit and cuts power (un-lock)to the tranny and LED.

That's using an ECM to lock up the tranny...don't know what lock-up system you are using.

I suspect that Jef will jump in and talk about proper TV cable adjustment..which is critical.

BTW: Some trans builder send out the 700R4 with the lock-up feature disabled and without lock-up torque converter....but for the lock-up solenoid to work it needs 12v power.

Ed

Senior31:
Ed,

      Thanks for the reply,  but unfortunately I am not running an ECM.  I am starting to regret this decision. I am running a crate 350 HO with a demon carb. So I am locking up off of vacuum.  I do have a power and ground going to the solenoid,  but I think it is actived by vacuum. I have checked and I am getting good vacuum, but I haven't checked it while driving. The only other thing I have considered is putting in Bowler's lock up kit. This does away with the vacuum and uses a timed delay to lock up the TC.  I really don't want to keep dumping money into this tranny, but I want to get it right also. Hopefully,  Jeff can offer some insight. Okay, I am done high jacking your thread moose!

EDNY:
Senior31

Hate to keep jumping myself...but one way to determine if it's locking up is to over-ride that vacuum switch (toggle) and drive the car...if you feel it stalling as you stop, like forgetting to push in the clutch on a manual car...you know the torque converter is locked??

To see if the vacuum switch is working why not wire in a small inline LED.

Ed

Sorry Moose...but would still like Jef clear up your original question...I know tranny shops offer the 700R4 without the lockup option (my buddy bought one last year).

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