700R4 TC lockup question
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Team Owner
Joined: Sep 2003
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From: Freedom is never more than one generation away from extinction.
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700R4 TC lockup question
When does the TC lockup?
My 86 will only lock if in 4th after 40 MPH (approx). I'm told this condition is not stock and has been modified to behave this way.
After talking with a 700R4 overhaul mechanic, it appears that the "stock" TC lockup will engage in 2-3-4th gears at speeds above 30 MPH.
Whats the REAL story here?
My 86 will only lock if in 4th after 40 MPH (approx). I'm told this condition is not stock and has been modified to behave this way.
After talking with a 700R4 overhaul mechanic, it appears that the "stock" TC lockup will engage in 2-3-4th gears at speeds above 30 MPH.
Whats the REAL story here?
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
It locks when the ECM tells it to lock. That assumes the transmission can accept the command. For instance, the 700R4 will not allow the TCC to lock while it is in first gear. If you don't like when it locks, you can have a new chip burned.
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Drifting
Joined: Mar 2004
Posts: 1,504
Likes: 0
From: Byron Center MI
Originally Posted by JrRifleCoach
When does the TC lockup?
My 86 will only lock if in 4th after 40 MPH (approx). I'm told this condition is not stock and has been modified to behave this way.
After talking with a 700R4 overhaul mechanic, it appears that the "stock" TC lockup will engage in 2-3-4th gears at speeds above 30 MPH.
Whats the REAL story here?
My 86 will only lock if in 4th after 40 MPH (approx). I'm told this condition is not stock and has been modified to behave this way.
After talking with a 700R4 overhaul mechanic, it appears that the "stock" TC lockup will engage in 2-3-4th gears at speeds above 30 MPH.
Whats the REAL story here?
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Around 40mph sounds abour right.
The good reason for lockup in 2,3,4 is economy; if you need power just mash the go pedal and the resultant downshift will bring the RPM up above the stall of the TC. Locked/unlocked is only an issue at low engine RPM, i.e. below the TC flash point.
I had a 2,000rpm TC installed and at 40mph in 3rd the tach is running close to that stall point so eliminating lockup is not desirable.
The good reason for lockup in 2,3,4 is economy; if you need power just mash the go pedal and the resultant downshift will bring the RPM up above the stall of the TC. Locked/unlocked is only an issue at low engine RPM, i.e. below the TC flash point.
I had a 2,000rpm TC installed and at 40mph in 3rd the tach is running close to that stall point so eliminating lockup is not desirable.
