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TCC lockup for rock crawling

Boss Hugg

Contributor
Bronco Guru
Joined
Jun 8, 2010
Messages
2,145
I saw danwheeler's post a few years back about using a relay and switch to lock the converter clutch on the 4r70w for braking help on downhills.

http://classicbroncos.com/forums/showthread.php?t=147680&highlight=Converter+clutch+relay

However, I just got my transmission working yesterday with a switch to do this and I think I've wired backward. Anyway, the books on this transmission said that the converter would not lock in low gear because it is hydraulically blocked in the valve body. Does anyone know anything on this? Did danwheeler's ever get this contraption working for him?
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,948
I did it, no relay.
Some valve bodies block lockup in low gear, others will allow it. At one time I had instructions on which hole to block in the separator plate to allow lockup in 1st gear.

The lockup solenoid wiring is very simple. It always has 12V supplied to it. The switched wire going to the computer simply puts ground to the solenoid when lockup is desired. Splice into the wire, ground as desired to lockup. I used a momentary pushbutton on the floor controlled by my left foot (not being used for anything else while driving an automatic).
 
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Boss Hugg

Boss Hugg

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I wish I had known I could block a hole in the plate last week, and of course, which one to block. I had the vb out to rebuild it thanks to a rusty crankshaft keeping the converter from sliding all the way up. It pushed on the pump gear and gaulded it, so I had to replace it and clean everything up inside the case.

Now, I'm dealing with it downshifting when I let off to slow down... Not sure what that is...


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Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,948
Gregg at Baumann gave me instructions more than a decade ago. Gave them away with the "file" when I sold the truck.
 

NYLES

Bronco Guru
Joined
Aug 13, 2004
Messages
9,846
I wish I had known I could block a hole in the plate last week, and of course, which one to block. I had the vb out to rebuild it thanks to a rusty crankshaft keeping the converter from sliding all the way up. It pushed on the pump gear and gaulded it, so I had to replace it and clean everything up inside the case.

Now, I'm dealing with it downshifting when I let off to slow down... Not sure what that is...


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Where are you getting all these transmissions?
 
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Boss Hugg

Boss Hugg

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Messages
2,145
Same transmission bud!


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Boss Hugg

Boss Hugg

Contributor
Bronco Guru
Joined
Jun 8, 2010
Messages
2,145
We have several vehicles at my place to pull from. This one came from the junkyard tho.


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