Transmission wiring

BAR-AIR

Well-Known Member
Good Evening,
Looking for information with regards to wiring (actually unwiring) a automatic transmission harness. Basically I have never really been happy with the way the automatic transmission shifts everything has to go through the TCM. Especially in auto cross events it tends to get confused and is shifting really early or very late. So I was getting ready to pull the automatic and install a manual but after talking to a couple people on the forum and the ease of which anybody can just jump in and drive the automatic I’m going to try one more thing to get it to work better.
So this is what I am trying to install...

TCM 920 Transmission Controller from E-TransControl
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It has a fully manual mode with converter locked and unlocked(actual line pressure control) and it also has an automatic mode... completely stand alone...
So here are where the question begin... how much of the OEM TCM harness can be removed.
8CEB2F3F-EEDC-45B7-8655-2A09CB0855B3.jpeg

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The above 3 pictures show the extent of the automatic transmissions harness. Relatively contained to it self.
Picture #1
Is the circular plug all wires from that go directly to the TCM
(with the exception of the pink wire which goes to the Black fuse block location 5-E then doubles back to the TCM).
Picture #2;
Wires from the TCM... only four wires go outside of the transmission harness
LT BLUE goes to the Black fuse block location B-5
RED/WHITE goes to Black fuse block location A-2
BROWN goes to Red fuse block on the BCM then doubles back to the ECU plug
BLACK goes to ground
DATA wires just go to and from the TCM
Picture #3
Wires from the automatic transmission selector on the transmission... only five wires go outside of the transmission harness
(2) BLACK go to ground
LT GREEN goes to the reverse lights
GREEN goes to the ECU plug
PINK/BLACK goes to the Black fuse block location B-5 (miss noted in picture)
E1AD439C-0B7B-4806-97D5-E251C3B317DA.jpeg

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Pictures #4-5
Just the Black fuse block and my notes...

Basic question... if I eliminate the entire TCM, circular plug, and selector plug.
if I tie the data lines together to eliminate that loop. What else will I need to keep?

THX,
Bruce
 

JSATX

Goblin Guru
I assume you have this info already if not there’s a few more pages with the other trans plugs too.
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Torchandregdoc

Goblin Guru
I'm very interested in this thread. I'm still months away from this, buy i will be here.

I think Jpr put a Manumatic in his car. I don't have time right now for research, but i think this is it
 

BAR-AIR

Well-Known Member
Good Morning,
Yes, I have tuned and re tuned trying to get the transmissions shifting point correct. Let me preface this with for normal driving not an issue maybe a late or early shift occasionally. On the track, hard driving the transmission tends to get confused. As in the engine (supercharger is screaming) and the transmission will lag up to a 3 to 5 count and go to 4th gear instead of 2nd. And yes JPR also has the ManuMatic version of the same controller (manual shifting only I believe no automatic functions). From talking to him he seems to really like the control of the transmission but his controller doesn’t have the line pressure adjusting capabilities so his shifting tends to be a little more harsh (great for the track not so much for street driving).
I have the original harness I had initially made for my car. I am using that one to cut the TCM completely out only a couple of wires I may need some help with identifying.
THX,
Bruce
 

BAR-AIR

Well-Known Member
All right first question. With my current harness the car will not start with the TCM unplugged. But will run if you start it with the TCM plugged in and then remove the plug once it is running. I’m guessing it is the Data wires need to be tied together to eliminate the TCM from the loop.
 

k.rollin

Goblin Guru
If you get one the rockerbox or switchblade shifter units, those have a knob to adjust line pressure. The TCM920 has that adjustment set in the programming.
 

BAR-AIR

Well-Known Member
That is what a got the rocker box with the line pressure and torque converter lock and un lock the TCM 920 also has an automatic shifting function.
 
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