Torque Converter Lock Up Sequence
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5th Wheeling
Joined: Jul 2013
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Torque Converter Lock Up Sequence
Can anyone explane how the torque converter lock up sequence goes? My Motorhome is a E450 it will not shift into overdrive unless speed is over like 35-40 mph. Will lock up happen as soon as trans shifts into Overdrive? If So is it supposed to unlock with a slight throttle application? What triggers the converted to unlock?
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,704
Likes: 2,625
From: SE Florida
The converter can lock in any of the forward gears if the conditions are right.
In first and second gears it can only lock if the accelerator is more than 75% of the way to the floor. In third and fourth it can lock at very low throttle openings. It can unlock when the throttle is pushed, if the speed drops, or if you let off the accelerator. The PCM (Powertrain Control Module - the computer) makes all of these decisions.
Most of the time the shift sequence is 1-2-3-converter lock-4.
In first and second gears it can only lock if the accelerator is more than 75% of the way to the floor. In third and fourth it can lock at very low throttle openings. It can unlock when the throttle is pushed, if the speed drops, or if you let off the accelerator. The PCM (Powertrain Control Module - the computer) makes all of these decisions.
Most of the time the shift sequence is 1-2-3-converter lock-4.
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