From my truck thread:
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E4OD's are actually pretty simple from an electronic control aspect. They have 2 shift solenoids, a torque converter E4OD's are actually pretty simple from an electronic control aspect. They have 2 shift solenoids, a torque converter solenoid, a coast clutch solenoid, and an electric pressure control thingy which operates off changes in current and controls line pressure. (Imagine a valve that acts like a stereo speaker connected to DC voltage) All, except for the EPC are controlled by grounding the solenoid to activate it.
Pretty simple stuff really and if a guy had control of the EPC, you could easily set it up like a manual valve body with just a few relays or switches.
Gear.........SS1....SS2
D1.............ON.....OFF
D2.............ON.....ON
D3.............OFF.....ON
D4.............OFF.....OFF
M2.............OFF.....OFF
M1.............ON......OFF
When the trans connector is unplugged, you have M2 and 4th because these are both completely hydraulic. This is how we are driving now.
Our problem is that with the connector plugged in and manually shifting, we have M1 and M2. In D we only have D1 but with no upshift to D2, D3, etc.
If you try to shift M1, M2, then D, you are met with a "neutral" situation when expecting 3rd, like it is not applying SS2. But, you would think that would result in 4th.
I still do not have a correct VSS signal and that may totally correct everything but usually a bad VSS results in high hard shifts, but it still shifts.
I jumpered SS2 to ground with a switch while in D and it shifted to 2nd, so I know SS2 works. That was a very big relief.
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We drove ours quite a while with the trans disconnected. It just started in 2nd and then would shift to 4th.
*********************
E4OD's are actually pretty simple from an electronic control aspect. They have 2 shift solenoids, a torque converter E4OD's are actually pretty simple from an electronic control aspect. They have 2 shift solenoids, a torque converter solenoid, a coast clutch solenoid, and an electric pressure control thingy which operates off changes in current and controls line pressure. (Imagine a valve that acts like a stereo speaker connected to DC voltage) All, except for the EPC are controlled by grounding the solenoid to activate it.
Pretty simple stuff really and if a guy had control of the EPC, you could easily set it up like a manual valve body with just a few relays or switches.
Gear.........SS1....SS2
D1.............ON.....OFF
D2.............ON.....ON
D3.............OFF.....ON
D4.............OFF.....OFF
M2.............OFF.....OFF
M1.............ON......OFF
When the trans connector is unplugged, you have M2 and 4th because these are both completely hydraulic. This is how we are driving now.
Our problem is that with the connector plugged in and manually shifting, we have M1 and M2. In D we only have D1 but with no upshift to D2, D3, etc.
If you try to shift M1, M2, then D, you are met with a "neutral" situation when expecting 3rd, like it is not applying SS2. But, you would think that would result in 4th.
I still do not have a correct VSS signal and that may totally correct everything but usually a bad VSS results in high hard shifts, but it still shifts.
I jumpered SS2 to ground with a switch while in D and it shifted to 2nd, so I know SS2 works. That was a very big relief.
*************************
We drove ours quite a while with the trans disconnected. It just started in 2nd and then would shift to 4th.
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