1990 F350 E4OD transmission shift Issue!
 

Hello all,

1990 F-350 Dually V8 460 Gas E4OD 2WD 78k miles.

• Codes: 11.......CM Codes = 21,41,77.
• No CEL.
• No blinking OD light.

Truck shifts this pattern > Hard 1st shift around 2k rpm maybe a little lower > 2 seems normal > 3 seems normal > then quickly again after 3rd which is OD I believe (Again seems normal).

Truck has a very hard 1-2 shift, rest of the shifts feel perfectly normal. It does get worse from cold engine hard shifting to 15 minutes later even harder. I am going to try to be as detailed as possible. I am kind of desperate for a solution.

I started by pulling the codes and as you can see from the above mentioned codes, none of them seem to be related to this shift issue.

I checked all the fuses in the fuse box. They all appear to be good.

I disconnected the battery prior to doing anything with sensors.

I have checked the MLPS to best of my ability and bought a new one just to be sure and cleaned the connection. I know for certain it is lined up.

I pulled VSS > clean > grease > reconnected. I have also tried a new VSS.

I pulled the speedo gear cable connector out and checked it out because I do have some speedo wobble at 25 to about 35 MPH. Speedo gear was in good shape and I looked inside where it sits and the internal gear looked okay also. Clean > grease > reconnect. Speedo wobble is still there slightly. (Note this is a 1990 with no PSOM to my knowledge since they started putting them inside 92 and up).

I pulled the solenoid connector > clean > grease > reconnected.

I checked the TPS and am getting what appears to be in spec voltage all the way to WOT and back down again. Cleaned > greased > reconnected as well. Have tried a new one as well.

I tried a new MAP sensor to no avail. clean > grease > reconnected the old one.

I pulled the ECM which appears to be a newer one as it says 2003 on it. I opened it and looked for fried electronics of any sort but there were no bulging/leaking/broken capacitors or board discoloration. Details for it are as follows. EFI - SD36E and FOTF - 12A650 - ATA.

Dropped the tranny pan, no significant signs of damage, fluid was a good red color, magnet did have a fine grey layer no large chunks. Cleaned it up, put in a new filter, gasket and tranny fluid (DEX/MERC III Valvoline brand). Have not drained the TC yet.

Next I learned what an accumulator was. Reopened the tranny pan, pulled the accumulator and solenoid pack because i needed to clean the inside of the connector as i couldn't get to it when it was in place. Opened all 4 accumulator valves and found broken springs in some, including the #2 accumulator valve (responsible for the second shift as far as I know) and also noted I found a spring seat in the line pressure valve which according to my research from factory it doesn't have one? So maybe someone has been in here before? Bought a Superior shift kit because I couldn't source individual springs and I performed the accumulator section of the kit (Replaced springs and the spring seat for the line pressure valve was already there). I did buy a different transgo kit that comes with 3 accumulator valves that replaces the old valves which were made of a certain metal that tends to stick and could cause some issues. Apparently the #2 AC Valve is notoriously sticky so I thought it couldn't hurt to replace all 3 of them with the new metal type. Put it back in the tranny and thought I had fixed it. Turns out after the truck went through the gears (about 2 minutes into driving) it went back to 1-2 hard shift. I can disconnect the battery and replicate these results.

I dropped the valve body yesterday and checked all the valves, they are all good to go. Springs were not broken.

Pressure Results are in and as follows;

P - 80-85
R - Flutters between 120-130
N - 80-85
D - 80-85
2 - 80
1 - Flutters between 120-130

Pressure test at WOT yielded the following;

D - 200
2 - 200
1- 240 - 250
R - Went beyond 300 and waved back and forth between 270 - above 300.



Other issues which may or may not be related:

A. The 3rd light above the truck bed is out and I replaced the bulb but it did not come on. Note: Since my vehicle is a 1990 this is a courtesy light not a 3rd brake light like the 94 and up 9th gen models have. In the 94 and up models, the third brake light being out has been known to cause some harsh shifting so in my instance this is not the cause.
B. The previous owner did mess with a few things electrical related and they are listed below.
1. He put LED light bulbs in the roof cab lights, and side marker lights, I know this upsets some older vehicles regarding hyperflashing etc. I will probably change them back to OEM bulbs just to be sure.
2. He wired the trailer harness to the front of the bed because he had a in bed camper. I don't know if he knew what he was doing and I am not 100% sure what I am doing when it comes to electrical stuff as I am still learning so I cannot verify if it was done correctly.
3. The previous owner was a firefighter and apparently he had a small pump installed under the bed that connected to the fuel and the wires run to a switch into a cab which if turned on shoots fuel out into the ground next to the truck. Im guessing this was to create a fire line quickly. I immediately disconnected the switch after buying the truck cause this is southern California and thats just a recipe for disaster if you bump that with your knee. I have the wires hanging down in the cab they appear to go to the back of the fuse box and I need to remove the wiring completely still.
4. There is a black sunpro tach installed just behind the steering wheel and I do not know if it is factory as my dash does not have RPM. It has a green wire running across the engine bay going to wherever tach sensors sense RPM and the wire is in two pieces about mid way through the engine bay and they are just twisted together for a connection. Not the best but according to the tach its working.

Thats all I have so far. Since me disconnecting the battery causes it to shift fine for the first run through of gears I want to say its electrical and not a bad internal tranny but thats just my guess so far. Please help!

- Shaun

bumpity bump

I do know that every time I've had a 3rd brake light issue i have had the hard shift syndrome! Start with that and then go from there.

Thank you. This will be the first thing I look into. Any advise on how to test this? I tried a new bulb but it did not light up. I do have a multimeter but I am not the best on testing electronics unless guided. Your help is appreciated.

Frist when does the third brake lamp come on? I want to be sure I am testing the bulb when it should be lit up and I am not 100% sure when its suppose to light up. Park with lights on? Doors open? Reverse? etc. Please advise.

For checking the wires this is my thought process. Correct me if I am wrong.

When opening the third brake light I see the bulb connector and two wires going to it. It appears these wires travel between the 2 layers of the roof to the front of the cab and probably down the A pillar to the fuse panel?

I am guessing the first step is to check if power is coming to the bulb connector. Ground one lead of the multimeter and then red lead to one wire and check it on volts? what voltage would be good? if not on one wire check the other lead. If there is voltage then re do the bulb connector if no power then go to A pillar/fuse box and trace the wires back to find where they connect and see if maybe they came undone?

Please let me know if this sounds good and any further information you can provide would be good.

Thank you - Shaun

It's just like it sounds,a brake light.This means it comes on with the two standard brake lights when you step on the brake pedal.

Your making way too many threads on the same subject though Shaun .What's this one,the third now? How are people searching in the future supposed to follow and learn from that? This is why it's against the forum rules.It's very hard for those trying to help you too.

Hello,

Yes this was the main original thread I made when joining this forum which I am updating/editing as I go along and trying everything people recommend for the 1-2 hard shift. So anyone looking to follow in my footsteps can.

I do have a thread on testing MLPS and Accumulator spring size. Anyone that has the same question I did can read that too. If that is too much then I guess that is too much.

If I was someone wanting to know how to test the MLPS I would search for it and find its thread. I would rather not have to search through a E4OD 1-2 hard shift fix essay. Separate topic, separate thread and if it overlaps solving this issue I include its step here. I have never been a part of a forum but this is the way I thought about it. Correct me if I am wrong.

Thank you - Shaun

Hello,

Update I went out and double checked, the third brake light does not light up the bulb is new and when I probe the connection with a multimeter I get .06 volts with key on.

Turn signals work, Hazards work, headlights work, side marker lights work, brake lights work, reverse lights work.

Thank you - Shaun

Checking with the key on doesn't tell you anything. You need to check for voltage with the brake pedal pressed.

1990 with third brake light??

Yeah good point.That didn't happen until the 9th gen in '94 I think it was.Before that (like my '93's) it's just an outside courtesy light.

Yes sorry forgot to mention I used a 2x4 and checked it with the key on and brake pressed. I get .06V.

Okay so its not a 3rd brake light but a courtesy light..... interesting. So should I be testing it in park key on? Do the two wires that go to it travel to the front of the cab and T into the cab lights? or do they go to the dome light or A pillar and down to the fuse box? I took trim off and started pulling the headliner back but I am still looking for where they go.

Thank you - Shaun

It turns on when you open a door with the interiors dome light.Working or not,will have 0% effect on your transmission.With the 9th gen trucks ('92-97) the interior dome lights circuit needs to work because the speedometer memory is on the same circuit (even on those trucks,that outside light doesn't need to be working,it just can't be shorted out causing the fuse to blow) but for your truck,there's nothing related about that outside courtesy light to effect the trans.

Go to your other thread and follow the pressure test info to stay the course on your firm shifting issue.

Got it thank you. Going to get a pressure reading now.

Note: If he finds a blown fuse on dome circuit, remove cargo lamp and push down on roof . The skin will contact the right screw holding interior light, Snow is the culprit. Been there.Wires run down left cab corner (inside).