Another hard shifting E4OD (Always)

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1996 F53 Chassis Ford Motorhome, 460 gas, 25,000 miles. Started a few months ago, about 400 miles ago. Shifts extremely hard in all gears, hot or cold. Seems to me I might have seen the OD light flash back then, but it was out of the corner of my eye, and I thought it flashed but was not sure. I cannot find the diagnostic data plug to scan it. I am about ready to start taking the dash apart. Any ideas on location of plug or diagnostics of transmission? BTW speedo works fine, it shifts at the right points, no unusual noises except the dishes rattling.
 
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I don't know what to tell you. Unless someone moved the connector every 1994-97 that we had at the some the DLC was mounted on the very bottom of the dash (half hidden) just above the right side of the trans tunnel. If someone moved it then who knows where it ended up. Normally if you get a flashing OD light and hard shift it's due to a decected slip and the PCM commands full line pressure, but there may other issues as well.
 

another Todd

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Finally found it under the engine cowling, to my shock and horror it is an OBD 1. Incompleted vehicle manufacture date of 11 1995. I thought for sure that should be an OBD 2. Anyhow I still have an OBD 1 tester and here is what it says. 625---Elect Press Control, EPC Driver, Open in PCM. Bingo. The only thin I can think of to check is the connection where I (7 years ago) installed a B&M shift improver controller. I think I had to tap into that wire, connection may have gone bad.
 

another Todd

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I put a ohm meter to both sides of the B&M electronic shift improver connections, and got 0 resistance so it is not that. Now looking for my gear vendors installation guide to see what was tapped into with that installation.
 
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You may have to pull the pan and check the solenoid's coil resistance. It's possible the solenoid failed, it does happen. If that is the case they are easy to change. And while you have the pan off I would install a real shift kit and install a large Line mod valve from Sonnax. Cost about 75 bucks and a few hours to install. If the wiring modifications you made are still sound, and the solenoid tests good then it may in fact be a bad driver in the EEC-IV.
 
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Just a suggestion, a voltage drop test would better show a bad connection than isolating the circuit and checking resistance through the connection with an ohm meter. The ohm meter test is very low current and may not show what is really happening when power is applied to the circuit. Red lead before the connection and ground lead after while circuit is energized. If you get much of a voltage reading, then you may have a connection issue there.
 
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I believe the circuit he is testing is a PMW circuit, so making an accurate Vdrop test under normal operating conditions is going to be very hard. In order to do a Vdrop test on that circuit and have a meaningful result you would have to isolate the circuit at the ECM and then provide your own power and ground making sure you have completely isolated the supply and return sides to the ECM to prevent back feeding the circuit drivers.
 
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10-4. Yeah, a PWM circuit is a bit different in that regard. Sounds like a harder test to set up in this case. Maybe better to just visually check the connections in question and make sure still tight and no corrosion.
 
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It shouldn't be too hard if you have a wiring schematic. You could islote the circuit simply by unplugging the entire harness from the ECM. Find the pins you need and power the circuit right from the harness termination. But you are probably right, to start off with it's probably be easier to just check the connections and make sure they don't fall apart in your hand and then move on to more difficult testing.
 

another Todd

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 Originally Posted By: 1040 WreckerMan
You may have to pull the pan and check the solenoid's coil resistance. It's possible the solenoid failed, it does happen. If that is the case they are easy to change. And while you have the pan off I would install a real shift kit and install a large Line mod valve from Sonnax. Cost about 75 bucks and a few hours to install. If the wiring modifications you made are still sound, and the solenoid tests good then it may in fact be a bad driver in the EEC-IV.
OK the connections seem solid. Would testing the solenoid resistance in the pan be the next logical step? What is a large line mod valve and what does it do? Is there more than one solenoid in the pan? What is the test procedure and values I am looking for? What transmission repair manual do you recommend that would show these steps? Thanks.
 
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Well, you can actually test the solenoid at the through case connector rather than pulling the pan. You'll need a manual to tell you what pins are for the EPC solenoid. Yes, there are other solenoids as the E4OD are completely electronic so solenoids control trans function. I'm not 100% sure what the EPC should ohm out at, but it will be in the 15-20 ohm range. ATSG is the transmission repair manual I would go with if that is what you were asking, otherwise a Ford manual is the only way to go. The line mod valve controls the transmission main pressure in cooperation with the EPC circuit. The new valves help maintain pressure at some level from stock to higher than stock. This along with a good shift kit works wonders on E4OD's and 4R100's. Most of the failures on this series of transmissions can be traced back to a few things, they had poor torque converters from the factory. The new service part is much better. The other major issue is the VERY poor shift quality. The shift kit will alter shift programming to both fill the piston faster and increases cooling, etc.
 

another Todd

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The B&M electronic shift controller I installed has worked great. It has positions for stock (long drawn out shifts), mild firm shift (faster more firm shifts) and full firm shift (immediate slam the gear shift). I use the mild firm shift position as the full firm is too harsh and of course stock slips way too much. I will probaby keep this unit installed. ATSG repair manual---where should I look to get one of these?
 
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The B&M is OK, but all it does is jack up the line pressure, which is not addressing the real issue. It certainly helps (to an extent), but it is not the way to fix the design PROBLEMs with the E4OD - it's a band aid. Just cranking up is hard on parts and actually hurts the transmission in several ways. The B&M on mild isn't going to hurt, but you are still really sliding the clutches on a loaded shift. You can keep your B&M resistor and still run a real reprogram kit if you wanted. But most are more than happy with the results of a reprogramed transmission by itself. Any transmission supply house will have ATSG trans manuals. Places like Makco parts (bulkpart.com), Transmission Parts USA, SeaTac Transmission warehouse, etc. They generally run about 15-25 bucks depending on the trans model and what version of the manual.
 
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