I can give that a try. Accelerate up to around 2000rpm or so then just let go of the throttle?
E4OD High RPM Shift Between 1-2
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Rdnck84_03
Full Access Member
Yes. If it immediately shifts, I think it may just be completely jumping over 2nd for some reason. I had that happen on 2 different 4r100s.
James
James
XOLATEM
Full Access Member
@Rdnck84_03 has a good point that I completely overlooked...that sure is possible on two counts...the intermediate sprag not holding and/or the shift valve not moving/ or dragging in the valvebody bore...
One other thing is the oil not getting to the intermediate piston via a leak between the valvebody, case, and piston housing...the area at the case where a hollow bolt is has been problematic..
Until you know for sure if the TCM is commanding 2nd...when it should be...you are going to continue to guess and try different stuff until you maybe stumble on something that works...
You need to tap into the harness and find the wire that completes the ground to the solenoid that actuates 2nd.
If you have a friend that has a break-out box...you can use that...
If not...then...
Look up 'signal monitor' on the internet and see if you can find a diagram for wiring up a test harness...
I have one...somewhere...but I can't find it from moving twice...it got buried...I am sorry...
One other thing is the oil not getting to the intermediate piston via a leak between the valvebody, case, and piston housing...the area at the case where a hollow bolt is has been problematic..
Until you know for sure if the TCM is commanding 2nd...when it should be...you are going to continue to guess and try different stuff until you maybe stumble on something that works...
You need to tap into the harness and find the wire that completes the ground to the solenoid that actuates 2nd.
If you have a friend that has a break-out box...you can use that...
If not...then...
Look up 'signal monitor' on the internet and see if you can find a diagram for wiring up a test harness...
I have one...somewhere...but I can't find it from moving twice...it got buried...I am sorry...
If you mean it's shifting 1 to 3, that's not the case. I can count (and feel) the shifts from 1-2-3-OD. It does do the 1-2 shift consistently when placed in drive, just at the high rpm I've mentioned. That being said I can give it the beans from 1st and then back of the throttle and see what happens.
XOLATEM
Full Access Member
This might help if you want to see if and when the TCM is actually commanding the shifts...
Rdnck84_03
Full Access Member
You should be able to feel what seems like 4 shifts. It is automatically in 1 when D is selected, so you should feel 2-3-TC lock- OD.
@XOLATEM has far more knowledge than me on the internal workings than me.
James
@XOLATEM has far more knowledge than me on the internal workings than me.
James
I do feel four shifts. I do a little test loop that's a few miles long and give me a few chances to run through all the gears as it requires a few stops. When accelerating to highway speed (60mph) the shift points are fine as you are giving 50% throttle or so to get up to speed. The issue is when you are burbling along in a residential area with a speed limit of 25mph or so. In that setup when you are light on the throttle the trans is staying in 1 and you have 2000+ rpm and feels like it should be shifting...
If at that point I manually shift into 2, it will shift, rpms drop and it holds the gear just fine. After I start accelerating out of the range for 2nd if I put it back into D it will pick up 3rd and hold it no issue. If I have to slow back down it will downshift back to second fine as well. It's a weird problem and probably one of the main reasons this truck got parked a few owners ago.
@XOLATEM I will check out the link and see what I can do to get some visibility as to what the transmission is thinking. I will go after the last few "easy" things to check, such as inspecting the PCM before I move on to the harder things.
I know I keep talking about the PCM, but I have a few reasons to suspect it.
1. This is a weird problem. Weird problems are usually electrical in nature
2. When I got the truck the EEC Relay and Connector were melted and ruined. I've replaced both damaged parts, but it's not the only evidence I've seen of something going very wrong electrically. The fan blower control switch and connector in the cabin were also melted. The main power wires to the glow relay are melted as well
3. I have an on again, off again code 22 for the baro sensor even with a working one. Since the signal wire for the baro sensor goes directly to the PCM, it throws more doubt that direction.
I probably won't have time to do any work on the truck today, but I'll try to do everyone's suggestions tomorrow if possible. Might be a few days before you hear back from me though.
1. This is a weird problem. Weird problems are usually electrical in nature
2. When I got the truck the EEC Relay and Connector were melted and ruined. I've replaced both damaged parts, but it's not the only evidence I've seen of something going very wrong electrically. The fan blower control switch and connector in the cabin were also melted. The main power wires to the glow relay are melted as well
3. I have an on again, off again code 22 for the baro sensor even with a working one. Since the signal wire for the baro sensor goes directly to the PCM, it throws more doubt that direction.
I probably won't have time to do any work on the truck today, but I'll try to do everyone's suggestions tomorrow if possible. Might be a few days before you hear back from me though.
XOLATEM
Full Access Member
That is probably a 3 wire sensor...power, (B+) ground and signal return...
If you have a DVOM I would check the circuitry into and out of the BARO sensor...check for good ground....check for good source voltage (B+)...and check for resistance on the wire from the sensor to the TCM.
In addition it would be good to check for AC ripple from the alternator...excessive AC leaking out can fuzz the electronics...
Sometimes I was able to fix head-scratchers by re-routing wires and harnesses that were inducing a voltage into other things...
Ther other thing to remember is...connections, connections, connections...
I have updates. The shift issue is exactly the same after checking the VSS. Didn't expect that to change anything... I did find a poorly done ground in the cabin. After fixing that all my chicken chaser lights work now, which is nice.
I did try cracking the throttle below 2.7kRPM to see if that would cause a shift. It did not. One thing I did notice is that if I manually shift to 2, then try to manually shift to 1 at a complete stop, it won't do it. I have to manually shift to D, then to 1 for it to actually be in 1st gear. Don't know if that means anything to the brain trust.
Did that KOEO test and the code 22 is staying away, which is good. I went to check the computer yesterday and when I put eyes on it in the cabin I saw that someone had written numbers on it in paint pen. That would mean it came from a salvage yard yes? Did Ford ever paint pen numbers on their computers? I intend to try and pull the computer today and run the engineering number to make sure it's the right computer.
I did try cracking the throttle below 2.7kRPM to see if that would cause a shift. It did not. One thing I did notice is that if I manually shift to 2, then try to manually shift to 1 at a complete stop, it won't do it. I have to manually shift to D, then to 1 for it to actually be in 1st gear. Don't know if that means anything to the brain trust.
Did that KOEO test and the code 22 is staying away, which is good. I went to check the computer yesterday and when I put eyes on it in the cabin I saw that someone had written numbers on it in paint pen. That would mean it came from a salvage yard yes? Did Ford ever paint pen numbers on their computers? I intend to try and pull the computer today and run the engineering number to make sure it's the right computer.
Updates. I pulled the computer and checked the engineering number. It comes back as a 89-90 7.3L Diesel computer, so it's the right one for the application. I then cracked it open and did a visual inspection and lo! A bulged capacitor! Tested it with the meter and it's dead. Also saw some corrosion crusties I don't like on some of the voltage regulators. I've got a new capacitor on the way and I'll clean the voltage regulators before I get everything reinstalled.
Cant Write
Full Access Member
Nice job!! I sure hope this solves it for you!!
Updates....
There was nothing wrong with that cap. I tested it once removed from the board and..... it was fine. Capacitance reading was exactly what it was supposed to be. Put the cap back in the computer and then buttoned it all up and did a test drive to make sure I didn't fry the computer. Computer did not fry, shift point did not change.
As an experiment I gave it the beans for the very first time on the highway and saw the computer DID change the shift points to hold onto the gears longer due to me having it at WOT. So... at this point I'm going to say the high shift in first is normal, or as close to normal as I'm going to get.
I'll continue to go through and fix the electrical issues as I find them, probably take a look at the FIPL again and adjust on it a bit to see what happens.
There was nothing wrong with that cap. I tested it once removed from the board and..... it was fine. Capacitance reading was exactly what it was supposed to be. Put the cap back in the computer and then buttoned it all up and did a test drive to make sure I didn't fry the computer. Computer did not fry, shift point did not change.
As an experiment I gave it the beans for the very first time on the highway and saw the computer DID change the shift points to hold onto the gears longer due to me having it at WOT. So... at this point I'm going to say the high shift in first is normal, or as close to normal as I'm going to get.
I'll continue to go through and fix the electrical issues as I find them, probably take a look at the FIPL again and adjust on it a bit to see what happens.
Rdnck84_03
Full Access Member
I wonder if someone who didn't know what they were doing tried changing the shift points? I am very unsure about what can be tweaked on the early tcm, have never messed with one. I know that the he early powerstrokes were completely tunable.
James
jbm6900
Registered User
My E4OD used to shift too soon, I plugged in a Banks Transcommand (dunno if they're still available) & it shifted Muuch better. Triple disc billet convertor is a good thing in those trans too.
