Torque Converter Lockout Switch
Fleet Owner
Joined: Aug 2004
Posts: 20,419
Likes: 197
From: AZ
I was pulling a 23K trailer moving down to AZ and forgot to flip the switch off. Several miles later the trans started slipping. I think I was at exit zero!
Thread Starter
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Hotshot
Joined: Mar 2012
Posts: 10,590
Likes: 382
From: Texas
Uh oh, really? What would cause it to slip if it was locked?
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,714
Likes: 2,640
From: SE Florida
Don't lock or keep it locked below 1300 RPM. The pump doesn't have enough output to keep the clutch from slipping below 1300 RPM.
Fleet Owner
Joined: Aug 2004
Posts: 20,419
Likes: 197
From: AZ
Maybe the disks in the trans, IDK. But my rpm's were fluculating and it was getting hot. Let it cool and the trans was good after that. All I can say is ask John, I have a feeling he wouldn't like it! But of course, IDK!
Laughing Gas
Joined: Feb 2014
Posts: 774
Likes: 25
From: Reno, Nevada
Yes, when I need more engine braking on steep hills I turn off overdrive and shift to second and if it's really steep I shift to 4WD Low.
That's good to know. Thanks
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Senior User
Joined: May 2013
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I put a switch on my torque convertor lockup when I put a switch on my EBPV. I don't need them or use them unless I'm towing down a steep grade. My brakes thanked me for the help.
My MO for using them: when approaching a down grade, I disable OD to get into third. If that's not enough, I shift to second. If that's not enough, I flip the torque converter lockup switch. If that's not enough, I engage the EBPV. If that's not enough, I shift to first. If that's not enough, I use the brakes. If that's not enough, I look for the truck emergency stop exits. If that's not enough, well, I'll just need to improvise cause that would be uncharted territory for me.
My MO for using them: when approaching a down grade, I disable OD to get into third. If that's not enough, I shift to second. If that's not enough, I flip the torque converter lockup switch. If that's not enough, I engage the EBPV. If that's not enough, I shift to first. If that's not enough, I use the brakes. If that's not enough, I look for the truck emergency stop exits. If that's not enough, well, I'll just need to improvise cause that would be uncharted territory for me.
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,714
Likes: 2,640
From: SE Florida
Logistics Pro
Joined: Oct 2008
Posts: 4,818
Likes: 1
From: Avilla, IN
Question 2, If you are using the TC-lock switch for extra braking and you need to downshift, should the TC be unlocked before shifting? OR can you just leave it locked in?
Thread Starter
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Hotshot
Joined: Mar 2012
Posts: 10,590
Likes: 382
From: Texas
Interesting. Is this why on my 96 I have to tap the brakes to get the TC to unlock, but on my 97 I just have to left off the throttle?
Question 2, If you are using the TC-lock switch for extra braking and you need to downshift, should the TC be unlocked before shifting? OR can you just leave it locked in?
Question 2, If you are using the TC-lock switch for extra braking and you need to downshift, should the TC be unlocked before shifting? OR can you just leave it locked in?
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,714
Likes: 2,640
From: SE Florida
