47re lockup od problem

B

bd blk 12v

Fixen broken bulldogs
Hello guys i been fighting this transmission for a bit. I installed a lockup an overdrive switch for my 96 4x4. The switches work great to lock and overdrive. The problem is when you shut the switches off. It stays locked. If you put the truck in neutral going down the road shut the engine off it will unlock and you can do it all over again. The trans has less than 300miles on it. Its rebuilt new electronics in It tfod shift kit dpc single converter. It shifts fine but won't unlock what am I missing? I've tried 3 different switches with no change.
 
Won't unlock even hitting the brake? Or just going to neutral then back to drive?


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No it will only unlock when the key is shut off. If you shut it off in neutral start it back up it works.
 
Try cutting the wire for lock-up down at the transmission connector and then only hook up your lock-up switch wire to the remaining short section of wire leading to the transmission connector plug, that way only your lock-up switch has control of the lock-up solenoid and see if it will lock and unlock normally when you flip the switch. The ground signal(trigger wire) for lock-up is the orange/black wire that connects to the #7 pin on the round 8 pin transmission connector plug.
 
We tried that bigblue24. It does the same thing and then throws the transmission in limp mode stays in second gear. I have no clue what is going on with it.
 
The PCM has to be flashed with a file from a gas burner.
Every time you lock it, it will limp and then operated like the OSS failed. I had mine flashed in 06.
Search around for it.
Mine was a late 95 built 96 model if that helps.
 
Last edited:
How does it stay locked if you cut the harness wire and kill the tcc ground with a switch? You have something else wrong.

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madmikeismad said:
How does it stay locked if you cut the harness wire and kill the tcc ground with a switch? You have something else wrong.

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I was a bit hasty. I wonder how long it has had a switch vs how long it's had a problem.
 
I have owned the truck 3 years it never had overdrive. I got tired of that I started checking and bought a snap on mt2500 and it would connect to the truck. I drove the truck checking pressure and the mt2500 showed 4th gear and the gauge would go up to 4psi then 0 no overdrive. I assumed the od seal was blown. My brother had a core and a guy I work with rebuilds transmissions. I bought a rebuild kit a dpc single converter tfod kit a band anchor and HD strut. Put the trans no od still. Now mt2500 wont connect. I thought let me try a switch setup I will control it. It worked shifted od and lockup. The first time in 3 years it felt good. I went to shut it off and it stayed locked killed the engine. I was like wth. My brother and I have been just fed up with chasing the same thing. Its odd you would think you controlling it, it cant go wrong but it does. We have tried 3 different switches. If u put it in neutral running down the road shut the engine off. Fire the engine up and its ready to do it all over again. I also bought new electronics for the trans when it was built. I'm at a loss. I was thinkin pcm I have one from a 97 but don't know what that will do. The truck is a 12-95 build truck. Thanks for the help.
 
Does it have a relay for the trans? (Not sure if a 96 does) if it does remove the relay and install a jumper wire and try it like that.
 
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