Been having an issue with the E40D in my '91 7.5l F350. Firstly, it bangs into reverse. But my main concern is that once it gets through the first 3 gears and reaches about 35mph, the RPMs just climb and I get no 4th gear or overdrive or whatever you want to call it. There is what feels like a slip or the TC unlocking when the truck should shift and the RPMs climb. It also has a harder 1-2 shift if given more throttle. Me being unknowledgeable had the trans replaced with a reman trans. Same issue. So unless they put bad internals in the brand new reman and I have a stuck valve or shift solenoid, I think I can rule out internal issues. Line pressure is good. MLPS has been replaced. Speed sensors have been replaced. TPS has been tested and deemed good. I have been an overwhelming amount of possible solutions to this issue and need more expert opinion. I have been told the dome light could be the issue (it works), throttle body needs cleaned, something about needing relearned or programmed, and I also have LED tail lights. The tails themselves have resistors. My "third brake light" is actually 4 LED trailer lights in a custom headache rack. They do not have resistors. The old incandescents burned out so I replaced them with LEDs. Can't remember if the trans issue started then or not. Rear diff fluid was recently changed. I was also told something about PSOM but I believe PSOMs weren't put in until '92. Other solutions I've been given include the ABS module, gear selector in the column not working right, relays, etc. So I'm sure it can be understood why this is so confusing when everyone has a different answer. Only code is 3-4 slip. I'm really leaning towards the LED rack lights being the issue but after a year of being plagued by this issue, I am done throwing parts at it.

 

ive got a spare E4OD in the Phoenix area - needs a new pump seal (i have one i will include) and a solenoid & gasket (again, got a spare solenoid but unsure of the condition, gasket is $17 from anywhere).

 

Have you even checked for codes?

For me, I would put the old school bulbs back in it for now. LED's are cool and what not, but not worth the cool factory when all it brings is trouble.

 

Only has a 3-4 slip code which I suppose could just be from the LEDs making the trans act up. I have new incandescent lights on the way.

 

The lights won't cause the bang going into reverse. Check your u-joints and if they're tight, take the trans back since it should be under warranty.

 

I have two transmissions that BANG/SLAM, etc into reverse.

The ATSG diagnosis, assumes all parts are stock and original to the truck. Does not account for incorrect parts, like a manual EEC in an auto.

First transmission was an internal problem.
Second transmission was an EEC problem. Wrong EEC for the transmission, it did not know how to shift into reverse, 1st or OD, and did not know how to use the lock-up.
Every gear felt like it was slipping since there was no lockup.

You have two transmission, one rebuilt and the EXACT SAME problem/issues persist?
- I'd have to guess you have wiring that is stripped/unplugged/bad grounds/no power to the transmission, or a bad EEC.
- Incorrect pin out on the MLPS

 

The more I read, sounds like the trans harness is unplugged.
Do you actually get 1-2-3 up shifts?
Does manual 1 and manual 2 actually feel like different gears?

 

Reverse is mechanically/hydraulically controlled. It will still work even with the trans unplugged. If it bangs going into reverse, there is a mechanical problem with the trans. Both issues could be valve body/ stuck valve issues. Something that might have simply been transferred between trans without testing.

My guess is, like so many E4OD's over the years; this trans was needlessly rebuilt, rather than properly diagnosed.

 

I disagree. Banging into reverse can be a wiring problem. If the circuit to the EPC solenoid is open the trans will be at max pressure all the time. That will bang into gear.

 

I have tested from the computer to the trans itself and the computer requests the correct voltages for different shift points which leads me to believe that it is indeed an internal issue which is perplexing because I was told that all parts including TC, shift solenoids, and valve body were included in the reman trans.

 

I do get all other gear upshifts, however 1-2 and sometimes 2-3 can be hard under heavier throttle. Manual gears feel fine.

 

MLPS was just replaced, however I did not replace the connector and it looks a little corroded. Harness looks good visually. I tested from the computer to the trans itself and the computer is sending the correct voltages for requesting shift points but the trans is not executing it. Leads me to believe that it is an internal issue which is strange because I was led to believe that all internal components were included with the reman trans.

 

Also leaks a bit of fluid around the pan gasket. Leads me to believe there is a pressure issue even though the fluid is at the correct level and line pressure has been tested and is good.

 

I put a trans pressure/temperature gauge in my truck. One of the best things I ever did. Knowing what I know, it is hard to believe that you can test the pressure and have the answer to be good. The pressure fluctuates all the time. Sure, it is fairly consistent when the truck is not moving, but that is about the only time it is consistent.

 

I have a diagram that lists each gear line pressure and hooked up a pressure gauge with a professional trans guy. It will show line pressure at idle and during a stall test. P, N, R, and all forward gears were within specifications according to my guy reading the gauge, which understandably makes little sense because of the hard reverse seeming like the trans is always at max pressure. However, I've been informed that if the circuit to the EPC solenoid is open, it can cause a hard reverse but this still means pressure is not correct. So whether or not the pressures are in fact within spec or not, I really believe this is an electrical issue somewhere, especially since the exact same issue persisted after a trans replacement leading me to believe whatever the issue is was on the truck before and after the trans replacement still unless parts from the old trans were swapped over to the reman for some reason even though I was told everything should be new internally.