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Discussion Starter #1 (Edited)
I'm currently reviving a 1968 Corvette 350 cu.in 300 H.P. currently having a TH400 transmission installed which shifts perfectly, but does not have the Overdrive gear or the Torque Converter Lockup.
I have already modified a TH700R4 for my 1934 SBC 350 cu.in. street truck, and it has shifted perfectly.
I realize I can install a base 4L60 or a TH700R4 with no problem, but I can get a great deal on a 4L60E.
Also, the 4L60E has the gear ratio I would like to have in the Vette, which only weighs 3500 lbs.

There are dozens of internet videos about converting the 4L60E to be shifted Manually by rewiring it for a floor shifter, but no one has been able to solve the EPC Force Motor rewiring problem.

THE MAIN REASON FOR REWIRING THE 4L6OE Force Motor IS TO AVOID RUINING/DESTROYING THE TRANSMISSION BECAUSE OF CONSTANT FULL LINE-PRESSURE WHICH CAN LEAD TO TRANSMISSION FAILURE OVER TIME BECAUSE OF HARD SHIFTS.

Problem #1 concerning the TCC PWM Solenoid(valve) can be solved by modifying the end of the valve body or the internal orifice diameter to a larger diameter so fluid can reach the Torque Converter Clutch at a faster rate which will engage the torque converter without "slamming the clutch" into full lockup (which would happen with Full Line-Pressure)

PROBLEM #2 IS MY HOLD-UP concerning modifying the EPC Force Motor. It DOES seem to require an in-vehicle computer to operate properly because of the low-voltage/ cycle-signal it receives from the vehicle computer. which causes the Force Motor to cycle On and Off about 30 times a minute in order to control shifting pressure.

My plan is to rewire the EPC using a relay/resistor/potentiometer to cause the EPC to function as though a in-vehicle computer is sending signals to the EPC.
MY PROBLEM is that I have limited knowledge as to how the relay/resistor/potentiometer can be wired to the EPC to make it operate correctly.

The Vette is "UNDER CONSTRUCTION" at the moment"

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ANY ADVICE TO REWIRE THE EPC FORCE MOTOR WOULD BE GREATLY APPRECIATED !
 

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Discussion Starter #2
Just checking in. I know someone on the Forum knows Someone who has rewired the Force Motor to work in a non-computer older vehicle...it can be a truck or SUV.
Thanks
 

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I am having my 4L60E remaned at a trans shop rite now. Its out of my 97 Silverado, with a Vortec 5.7 350. I have rebuild a few transmissions years ago. I will never do another one. It is something that I will pay an expert to do for me. They are doing a HD rebuild kit with hardened sun shell and corvette servos for about $2500. If I was trying to pull off what you are, I would be using a trans controller for the 4L60E. So here is the thing I have been asked, and will ask you the same. Why not a 4L80E. After all that is a new turbo 400 with OD and electronics as Im sure you all ready know.
 

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I am having my 4L60E remaned at a trans shop rite now. Its out of my 97 Silverado, with a Vortec 5.7 350. I have rebuild a few transmissions years ago. I will never do another one. It is something that I will pay an expert to do for me. They are doing a HD rebuild kit with hardened sun shell and corvette servos for about $2500. If I was trying to pull off what you are, I would be using a trans controller for the 4L60E. So here is the thing I have been asked, and will ask you the same. Why not a 4L80E. After all that is a new turbo 400 with OD and electronics as Im sure you all ready know.
It's a good idea to get a dependable rebuilder to do the nasty part. Basically, you are paying a little extra for the labor. All I will be saving is the labor charge because I will upgrade internal parts as needed, Why: I think the 4L80E has different gear ratio...I like the 700R4/4L604L60E gear ratios better...and the E-version won't be 30+ years old (which doesn't matter if you find a good rebuildable one)

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Got yua. I like the chart. I had a 72 Nova way back when, with 350 and powerglide. No wonder that car was a dog.
 

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My plan is to rewire the EPC using a relay/resistor/potentiometer to cause the EPC to function as though a in-vehicle computer is sending signals to the EPC.
MY PROBLEM is that I have limited knowledge as to how the relay/resistor/potentiometer can be wired to the EPC to make it operate correctly.
You know you can now buy 5-12V input and 1 amp variable duty cycle output PWM DC motor speed controllers on amazon that has LED display for duty cycle. You don't have to build from scratch. The PCS (pressure control solenoid) is duty cycle controlled from 0-50% max by the PCM according to the manuals available online. 0 duty cycle is highest pressure (115 psi maybe) and 50% duty cycle is lowest pressure. Max amps is 1.0 amp. You can manually adjust the duty cycle to adjust the torque control on the hydraulic circuit. You will need to hook up a pressure gauge to the transmission and adjust the duty cycle and create a table for line pressures vs amperage on the PCS.
 
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