89 7.3 do with transmission issue

[Jerredbaker]

I have recently bought a 89 f250 7.3 idi with the E40D transmission. The truck had been parked for 8 years due to a bad injection pump after replacing pump the truck drove good. While driving today it was like it shifted to neutral and would not pull in any gear including reverse no overdrive light flashing but also the overdrive light won’t come on when button is pushed any insight would be greatly appreciated

 

[nelstomlinson]

Sounds as if maybe you lost power to the transmission controller? Any one know what fuse to check? I think Ford called that the PCM?

 

[BeastMaster]

Be careful. Verify "Park" is working!

The parking pawl in the transmission may not be able to keep you from rolling away.

Does manual 1 or 2 work ( steering wheel lever ) ?

Chock your wheels. Especially if you are even thinking about a jack or going under the truck.

Are the drive shafts intact?

If you jack one of the rear tires off the ground, can you rotate it by hand?

Is the mechanical linkage between transmission and the selector lever intact?

Transmission fluid OK? Burnt?

I am leaning toward no line pressure or band failure, or possibly the torque converter. If this was in my hands, I'd be calling my transmission guy.

The E4OD is a common transmission in heavy Fords. It was designed with several limp home modes, obviously none of them are helping. I believe it was designed to limp home even if total PCM fail, albeit only in first and second gear, done hydraulically, and reverse by manual selection, which you have already noted as no-go.

This looks to me like it's time to call in someone who specializes in transmissions. I have no real-world experience in this; for this post I am parroting back my understanding of what I have read. So take what I offer with that in mind.

 

[DirtyWood]

An OBD1 code reader would be a place to start. No PCM on an '89 but there is a transmission control module/unit behind the driver side kick panel. The plug is on the engine side of the firewall--tall and thin plug with a single hex bolt holding it in place. Verify those wires are not chewed up or damaged. Verify the fuses are all accounted for and functional. Verify the plug on the passenger side of the trans is in good condition--it should be behind a small heat shield. Again, a code reader would help. I got an Innova OBD1 reader from AutoZone for $30, worth it in my opinion.
You can always drop the pan and check for metal shavings or other obvious physical damage. If there's a magnet in the pan then a small amount of metal fuzz on it is acceptable/normal.
Supposedly the transmission will still function even with total loss of power to it but that's just what I've read in a forum post so don't take my word for it.

 

[IDIBOBS]

If the of light will not turn on this is an electrical issue not a hard issue or pump issue. Some people like to go all out before ruling out basic stuff. Most likely the transmission relay is not working any more. If you check trans fuse and it’s ok the next step is the trans relay. It’s on the drivers gender some place. Check it for incoming power and see if it clicks when you turn the key. Measure out out power

 

[IDIBOBS]

An OBD1 code reader would be a place to start. No PCM on an '89 but there is a transmission control module/unit behind the driver side kick panel. The plug is on the engine side of the firewall--tall and thin plug with a single hex bolt holding it in place. Verify those wires are not chewed up or damaged. Verify the fuses are all accounted for and functional. Verify the plug on the passenger side of the trans is in good condition--it should be behind a small heat shield. Again, a code reader would help. I got an Innova OBD1 reader from AutoZone for $30, worth it in my opinion.
You can always drop the pan and check for metal shavings or other obvious physical damage. If there's a magnet in the pan then a small amount of metal fuzz on it is acceptable/normal.
Supposedly the transmission will still function even with total loss of power to it but that's just what I've read in a forum post so don't take my word for it.

An obd1 reader won’t work if the trans is not getting power.

 

[BeastMaster]

It is my understanding one should have reverse, 1, and 2 if the transmission is intact, regardless of the controller.

That is the "limp home" mode.

I am still going through an intermittent transmission problem, shows up every few months, then goes away, only to show up again.

Everything in me says it's an electrical issue. I have every piece of diagnostic equipment imaginable. What I don't have is the fortitude to butcher my wiring harnesses to hardwire in test connectors. I have to do this, so I have ordered a kit of assorted automotive connectors

https://www.amazon.com/gp/aw/d/B0B28TZ59X?psc=1&ref=oilburners-20

And wire 'em in...since I get six pins per connector, I can reserve, say pins 1 and 6, for ground and power

 

[IDIBOBS]

It is my understanding one should have reverse, 1, and 2 if the transmission is intact, regardless of the controller.

No this is not correct. Reverse will work. Even if you put it in 1 it won’t drive correctly and if you put it i 2 it will start off in 2 but move very slowly. If you do t have an OD light it is an electrical issue. Now you may have other issue but you must get the computer to work before anything else.

 

[BeastMaster]

Thanks! I haven't tried this with no controller, just parroting back what I understood from what I have read about. I was under the impression that the 2 and 1 on the PRNDL gear select lever on the steering wheel overrode all else ( but I have observed that the TC or coast clutch operation doesn't seem to be inhibited if 1 or 2 is manually selected, and I haven't disconnected the TCM. The TCM still seems be trying to control the transmission ). I am still trying to determine what's going on. I keep trying to catch it in the act.

Thanks for the update!

 

[Black dawg]

The e4od WILL have reverse and some forward gear, seems like 2 or 3, even with no electrical hooked to the transmission.

Edit.. I guess my reading comprehension was lacking yesterday, as I thought someone had said that the e4od would not function at all without the tcm...

 

[Black dawg]

What happens when you put the shifter in park after trying reverse or drive?

 

[Jerredbaker]

Thanks for all the input I swapped the torque converter and that fixed it the old one had come apart on the inside

 

[BeastMaster]

Thanks for the report!

You know, every time we use this forum, we not only help ourselves, but also the hundreds of guests who drop in just to read our stories. I have sure learned a lot from just reading the forums here...and more. There is one member here who left a lot of guidance on "Walking the Red Road", the wisdom of which has heavily impacted me.

I was thinking maybe you had lost line pressure and could not engage anything, as no hydraulic pressure to hold the bands. Maybe someone knows a quickie test to discern a failure of line pressure - compared to the torque converter fail - without cracking the transmission open. I guess there's a port somewhere a gauge can be attached?

I now have the benefit of your experience to help myself or anyone else I find in this situation.

Thanks!

 

[BeastMaster]

The e4od WILL have reverse and some forward gear, seems like 2 or 3, even with no electrical hooked to the transmission.

My understanding is that the mechanical position of the gear select lever will still give you Park, Reverse, Neutral, L1, and L2, however all shifting to the higher gears, Coast Clutch, and Torque Converter Lockup Clutch requires the PCM.

Now, it's been my experience that my PCM, given terribly buggy sensor data, couldn't make up its mind about locking the TC or Coast Clutch, or something...all I could tell is something was really buggy, and my attempt to force a steady second gear by L2 wasn't having the desired effect...something else was also influencing the transmission. Maybe, had I simply unplugged the TCM from the E4OD solenoid pack, I might have had full uncontaminated control of L1 and L2 via manual gearshift lever selection.

I recall many years ago when Ford wes first releasing this new electronic transmission, they were referring to its "limp home" mode that was intended to guarantee lol that no matter what went awry with the sensors or controller, you would get home, just not very fast. They were introducing the Coast Clutch and the ability to lockup the Torque Converter, for improving fuel economy.