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Old 02-10-2019, 06:55 PM
bigbill78 bigbill78 is offline
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Default 4r100 possible ground issue

I have an 02 f350 drw 7.3. I have a Hercules transmission and torque converter built. I got about 2500 miles on them when my over drive light started flashing (po743). I call the company and they sent me out a new torque converter and solenoid pack I changed them same thing I also noticed that my heater blow and my exhaust brake was not working so I got new fuse panel and pcm still the same thing so I changed all firewall grounds and transmission ground still the same thing. Any ideas from anyone out there. Also can I take the 6 grounds that go to pcm and hook them straight to the ground post on battery?

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Old 02-11-2019, 04:59 AM
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Originally Posted by bigbill78 View Post
I have an 02 f350 drw 7.3. I have a Hercules transmission and torque converter built. I got about 2500 miles on them when my over drive light started flashing (po743). I call the company and they sent me out a new torque converter and solenoid pack I changed them same thing I also noticed that my heater blow and my exhaust brake was not working so I got new fuse panel and pcm still the same thing so I changed all firewall grounds and transmission ground still the same thing. Any ideas from anyone out there. Also can I take the 6 grounds that go to pcm and hook them straight to the ground post on battery?

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You can hook grounds up anywhere but id add grounds and run them all to the battery or from the factory locations to the battery or just link them all together. Might be more than a ground issue and its the wiring itself.

Id pm mark kovalski or wait till he chimes in.

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  #3  
Old 02-11-2019, 06:37 AM
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Mark Kovalsky Mark Kovalsky is offline
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Why do you think it's a ground issue?

I think it's a damaged wire between the PCM and the transmission connector. Specifically, I'd look at the wire that controls the torque converter clutch solenoid.

I wonder why they sent you a new torque converter? It is impossible for the torque converter to cause a P0743 code. That code can ONLY set due to an electrical issue. There is nothing electrical in a torque converter.
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Old 02-11-2019, 10:55 AM
bigbill78 bigbill78 is offline
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Originally Posted by Mark Kovalsky View Post
Why do you think it's a ground issue?

I think it's a damaged wire between the PCM and the transmission connector. Specifically, I'd look at the wire that controls the torque converter clutch solenoid.

I wonder why they sent you a new torque converter? It is impossible for the torque converter to cause a P0743 code. That code can ONLY set due to an electrical issue. There is nothing electrical in a torque converter.
I installed a new conector from transmission back 12" had same issue then I ran new wire from pcm to the tcc wire same issue. Shift solenoid 1 and 2 or pin 2 and 3 are grounds as well right? Can I just run new grounds off them wires?
Went to ford to get a wire diagram and I had ford head tech transmission tech and there wiring tech and asked if I can wire new ground to pin 2 and 3 and the answer I got was (I think so)

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Old 02-11-2019, 01:28 PM
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There isn't any wire that needs to go to ground from the trans connector. There is +12V at the red wires whenever the key is on and the PCM provides grounds to turn the solenoids on or off.

If you run those wires to ground both solenoids will always be on and you will always be in second gear.
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Old 02-11-2019, 04:31 PM
bigbill78 bigbill78 is offline
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Quote:
Originally Posted by Mark Kovalsky View Post
There isn't any wire that needs to go to ground from the trans connector. There is +12V at the red wires whenever the key is on and the PCM provides grounds to turn the solenoids on or off.

If you run those wires to ground both solenoids will always be on and you will always be in second gear.
Now how do I go about testing the transmission plug?

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Old 02-11-2019, 07:16 PM
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Mark Kovalsky Mark Kovalsky is offline
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I've never tested just a plug. I check a harness from one plug to another. Unplug both ends of the harness and probe the BACK of the connector. Never push a probe into the end that makes the connection, that opens the pins and causes new problems.

Check each circuit for continuity, short to ground, and short to power.
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Old 02-11-2019, 07:45 PM
bigbill78 bigbill78 is offline
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Quote:
Originally Posted by Mark Kovalsky View Post
I've never tested just a plug. I check a harness from one plug to another. Unplug both ends of the harness and probe the BACK of the connector. Never push a probe into the end that makes the connection, that opens the pins and causes new problems.

Check each circuit for continuity, short to ground, and short to power.
I will give it a try and let ya know

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Old 03-02-2019, 07:17 PM
bigbill78 bigbill78 is offline
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Sorry it took me so long to get back with results. I just got time to go over everything. I found the issue the wires were pinched on top of the transmission got it fix and all is good. Took the truck out for a good 100 mile drive today and I was about 3 miles from home and my overdrive light came on and heard a pop and now I got a high pitch whine and the code that popped up was po741 could it be the pump that went out?

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  #10  
Old 03-03-2019, 06:21 PM
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If the pump went out you'd know it because the truck would stop moving.

P0741 means the torque converter clutch isn't locking when it should. That could be a stuck valve in the pump body, a seal on the input shaft, or a bad torque converter. It isn't the pump.
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