90 F250, 7.5. Had a super lazy 1st, so it has been parked for a while. Did a fluid change, nothing noticeable in the pan. Had to go to the dump today and the other truck was hitched to 2yds of 50/50, so no choice. Same issue. Had to wind it up to 4k to get it to go up hill after one stop/turn. Then 2 was lazy, and then off to the races. Next stop, 1 and 2 were like brand new. Get to the dump, and no reverse. Ah. A roaming chunk of crud. Now probably goofing up the reverse valve. On the way home, 1 and 2 were flawless. At least now I know most likely what is the issue. Time to drop the pan and the valve body. I'll take that over a total rebuild any day. Was only able to change half the fluid last time as the TC Is the type without a plug. Should get it all this time. Might start collecting the stuff for a manual swap while I'm at it...

 

Are you sure your engine is running properly?
Notice you didnt check FOR CODES


What does using the Manual 1 and 2 do, and does using the overdrive cancel switch do anythingg

 

A “roaming chunk of crud” making its way through the valve body that fast with “nothing noticeable in the pan” doesn’t make any sense to me. As was mentioned the transmission is completely computer controlled so why haven’t you checked for codes before taking it apart?

 

There are no codes. Or, none before yesterday's drive. I will check again, but being as there were not any before, I don't expect any after two cycles. I'm not the first person in this thing, but probably the second. I bought it with 78k on the clock, documented. Someone replaced some of the seals back around 60k because 30YO soft parts become hard parts. This thing sat around for a long time. It was a horse trailer hauler out in CA.

Manual 1-2, no change. Was still the lazy 1 engage until that 'resolved' during the drive.
The original lazy 1 engage was coming on slowly. I rented a car trailer from Ur-Screwed to go get a tractor a while back. The tongue brake on the trailer was bent and the right brakes kept randomly applying shaking the truck. This went on for a short period of time while I turned around to return it.The lazy 1 was significantly more lazy during/after which is why I parked it. I thought I might have a harness issue (mostly broken wire, higher resistance, slower solenoid action) that the shaking made worse. Again, no codes. That's when I did the fluid change so I could also investigate what was in the pan. Problem remained, so it stayed parked until I could get to it. I have another truck. Sat that way until yesterday other than moving it around the yard occasionally.

Thinking hydraulic, if a port has a partial obstruction, then the pressure is lower as it is a function of the cross sectional area. This aligns with a lazy 1 apply. Maybe that was still in the window of timing for the pressure so a fault would not be set. Obstruction moves, so now the 1 apply has full flow and acts normally. Wires don't mend themselves like that, so my earlier wiring assumption is most likely incorrect. Obstruction now interferes with Reverse apply, as in absolutely no apply. Silence. No light 'thunk' of going into reverse. So something is probably shedding. Intermediate clutch return spring? Those little skinny fingers have never sat well with me. It has no actions that would make me think that's the part other than the tiny fingers that can go places once shed. Coagulated crud from sitting 20ish years? Will find out when it comes out.

 

Unless you can prove your thoughts, thinking is a terrible way to diagnose. Facts will get you somewhere, thinking will too, but usually not where you want to go.

If the transmission is not shifting the way you want it to, it is because the computer is making it shift incorrectly or the computer is not making it shift but the transmission is doing it's own thing. Until you find out if it's computer or transmission issue, you will be going no where. No one can help you at all.

So, perform some basic electrical tests to confirm the solenoids are working to make the shift or not. Once you find out what the computer/electronics are doing, only then can you take the next step.

Or, you can just keep telling us what your symptoms are and what your thoughts are. That way has never really did much for me. Everyone has a good opinion but if you want to fix this, it's time to gather facts.

 

No codes as in the check engine light is not on? It doesn’t have to be on for there to be codes. No codes as in you aren’t getting any response from the computer or did you get code 11/111 from both the KOEO and KOER self tests?

 

So many assumptions, it's hard to begin. I know you don't know me. I didn't sign up yesterday. I have code readers, plural. In my previous diagnosis, many months back, I used the reader and found no codes set. I have the FSM for everything I own, some specialty dedicated subsystem manuals, and specialty tools both bought and fabricated. I have been working on my own vehicles for over 40 years. I am an Electrical Engineer by trade, and was designing with microcontrollers at the same time this truck was built and am very aware and capable of troubleshooting electrical systems. So now, you know something about me. I think the big thing missed here is I have not asked for any help yet. I'm sharing my experience and thoughts about it. Isn't that what forums are for? It's easy to assume someone has not been thorough in their actions. I'm not trying to write a novel about it either, yet here I am. This is similar to the 'Cop' syndrome. You deal with a majority client that is uninformed (wha iz ma truk brok?), so everyone is uninformed. I don't take any of this personally. I come here for the fun of it. E is for Enthusiast, and while I will not be buying anything modern from the Recall King ever again (and there is a story there), I will still enjoy my old rides (plural) and keep them road worthy. It's a hobby. One of many for me. Done for enjoyment. Let's keep enjoying it. I intend to do just that.
I do appreciate the replies. It's good to have a community dedicated to similar interests with a wealth of knowledge from which to draw. I will report what I find, which to date is nothing. Nor have I taken anything apart.
Thanks, everyone.

 

Yes, assumptions are made because we do not know each other. We all tend to give a quick answer/help with the few words that have been typed.

One of the assumptions of mine is I have not read that any 'real' diagnosis has been done. Just a bunch of hunches and thoughts. This is all good but the Y in the road is, do you have an electrical issue outside the transmission or an issue inside the transmission. The quick answer is do you have electrical signals telling it to shift or not?

You have not provided that information and therefore I assumed that you can't or don't know how. Since you are an electrical engineer, I am certain you get what I am saying. An electric solenoid is not going to move if there is not power/ground to it. So if someone says the solenoid is not working, you can think about it all you want, but until a test is done, all you are going to be doing and thinking and guessing.

I am just a mechanic, like you 40+ years. I tend to just say it as it is. Sometimes, it does not come out right and sounds harsh, I'm not trying to be, but I totally understand you might not believe me.

As I mentioned, the Y in the road is if the ECU is telling the transmission to shift like that or is the transmission doing it on it's own. Once you know that, then you can figure out where the next Y in the road is. If you look at the big picture, it just looks like a huge road map with so many roads to travel.

That is where I would invest all my time.

 

The transmission harness is a main concern
A good visual inspection of the connector and whether or not any trans fluid has contaminated the connector or not
I usually pull the connector up and off the E4OD and check for it to be dripping wet with trans fluid
I have a NGS and you do not - dammit
This is what you want for a 1990 with a E4OD
With this, you can command the trans to shift, and see if it does, plus check the codes and a few other trans related things on a 1990 E4OD

 

Not to get off the track too much, but does the NGS tell the EEC-IV to make the shift or does the NGS actually send the command to the transmission? Just curious. The more you talk about this, the more I want one. Sadly, I would never ever use this but for me. Hard to justify buying some ancient diagnostic tool that would crap out when I need it the most.

 

The scan tool commands the trans through the processor wiring down to the trans
When in active command mode then scan tool communicates directly with the trans but the processor plug and the processor itself relay the info to the trans
Same as the 4x4 shift motor on the T case, you tell it to shift, the command still goes through the GEM module because that is the wiring path

 

1Butcher, understood. I will follow a logical path to the conclusion.

Neat toy. Made me look at repair harnesses which I could attach to a little board to direct drive the transmission solenoids. This could be a thing. Interchangeable harnesses. Little 12V prismatic battery. LED indicators. Could even Bluetooth/Wifi it.

 

That NGS came out in 1992 IIRR so, for your 1990, it can all be dealt with using a basic superstar 2 tester and a breeakout box and DVOM
That procedure and the related pinpoint tests associated with the codes you come up with will fix the truck
You might find shift solenoid codes and will need pinpoint tests out of the PCED
Best of luck
Code test is first

 

I was about to say, you could do a quick test, but you can only do this with an IDI truck, cus we have trans units only. We're able to pull the TECA relay and kill the power. Then we can see what the trans is doing without electrical.
Without power to trans you should have;
1&2 in both manual 1/2 shift positions.
4th gear in D position.
R remains unchanged; working hydraulically.
But you can't do that with a gas truck, cus it's also the ECM for the engine. I suppose (unless a guy here knows this wont work for a reason I don't) you could accomplish the same thing by simply unhooking the solenoid pack connector right at the trans.
The thing is, you'll be starting in 2nd in anyway, so you couldn't test a 1-2 shift hydraulically by itself. You could at least start though by insuring you had what you're supposed to have hydraulically, without power. That's still a quick easy worthwhile test.

Well, unless manic sells us all his nice snazzy tool, there's a fee method too:




It does sound like you just have a worn out trans, but you'd be surprised what loose feed bolts and valve body bolts will do. They can make a good trans work just like a worn out one too. I think it wise to get in there and at least take a peek, like you plan to do, too. Who knows, you might see something very obvious.

 

TLDR

If there are no codes then the cause is something that doesn't throw a code. Also, one symptom can have multiple causes. Still, there are things to check before things get expensive:

If the fluid is red and doesn't smell burnt, it's still good.
When you drop the pan check torque on the valve body bolts.
A little bit of debris on the magnet in the pan is no big deal.
Ensure the filter is seated properly when you put it back.
Test the solenoids.
Replace the gasket with a rubber/reusable one, if yours isn't already.
Don't overtight the pan bolts.

I'm no expert. Just sharing what I've gleaned from this forum over the years.