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I have a 90 f150 5.0 E4od 4x4 that I got for $300. I put a rebuilt 5.0 that I had from an 89 bronco in the the f150, and I never had a chance to drive the truck before I did this. So my problems started when I went to take the truck for a test drive after I put the engine in and the transmission didn't seem like it was shifting right. I checked the ATF fluid and it wasn't burnt, didn't have a bad smell, and it was full. I have changed the filter and fluid in the transmission cleaned the MLPS and the plug that goes to the packs on the passenger side of the transmission, and still the transmission doesn't shift right.
The way the transmission is acting is kind of like it's in limp mode. It shifts in all gears though as long as you don't floor it. If I take off in first gear and floor it the rpm's will go up and it will stay in first for about 30 seconds and then shifts. If I'm in second or third and I floor it it drops a gear and stays in that gear for about 30 seconds and then shifts hard again.
This problem has been going on for months and I've talked to multiple mechanics about this problem and no one seems to know what could be causing this. I started pulling codes the other day and I did KOEO and KOER tests and only came up with a few codes but nothing that would be causing the shifting problem I think.
For the KOEO tests the codes that came up were 18 & 33
For the KOER tests the codes that came up were 12,44,33
I wouldn't think any of these would cause the transmission not to be shifting right but I'm really not sure. This is the first Ford I've worked on with the electronic controlled transmission and everything I've read about to do to the transmission hasn't worked.
Please help I am absolutely stumped. Any help or ideas of what could be wrong with it are greatly appreciated! Thank you!
Is it hitting the rev-limiter when it hangs in a gear? You shouldn't be able to stay in 1st gear for 30 seconds floored without the engine running right into the rev-limiter - around 5200 RPM or so.
Is it hitting the rev-limiter when it hangs in a gear? You shouldn't be able to stay in 1st gear for 30 seconds floored without the engine running right into the rev-limiter - around 5200 RPM or so.
It's not quite hitting the rev limiter. I wouldn't run it that high. It might actually be shorter than 30 seconds but it feels like it. I would say it gets to about 4600-5000 then it shifts, but sometimes it shifts smooth and sometimes it shifts hard, but either way it will stay in that gear for a while before it shifts. And also if I'm going down hill I can go through every gear no problem but up hill it doesn't want to shift at all
So what do you do to stop from over revving? Do you let off on the pedal, and then it still doesn't want to shift?
If so, I think you either have a TPS or VSS issue. Does your speedometer work?
I just let off the gas and it shifts and then I just slowly get on the gas again.
I changed my TPS not too long ago, but I did not know they were adjustable and I'm not too sure if I have mine adjusted right. My speedometer does work but it is off a little about 5-10 mph below actual speed, but I'm assuming it's because of the bigger tires. They are only 32's
The TPS are not adjustable. As long as the idle voltage is below 1.2 volts the computer is happy
Your speedometer reading 10 MPH off could definetly cause a late shift. I would get underneath, pull the speedo cable and housing out of the transmission and transfercase. Inspect the speedometer drive gear for signs of damage, and check the wiring going to the speedo drive for signs of damage or corrosion.
The TPS are not adjustable. As long as the idle voltage is below 1.2 volts the computer is happy
Your speedometer reading 10 MPH off could definetly cause a late shift. I would get underneath, pull the speedo cable and housing out of the transmission and transfercase. Inspect the speedometer drive gear for signs of damage, and check the wiring going to the speedo drive for signs of damage or corrosion.
I checked my speedo cable and gear and everything looked fine. I took the truck for a short drive again and it still does the same thing. If I were to unplug the speedo for the back of the gauge cluster would that maybe work? Or could that mess something up? Also could any of my problems be coming from the VSS? I believe it's the sensor on the pumpkin of my rear diff. I might be wrong though, this is the first truck I've had with a VSS my 89 bronco and 84 f150 I believe do not have the VSS.
The VSS on the 1990 is only used for the ABS. The engine computer gets its speed signal from the module mounted right on the speedo cable where it goes into the transfercase.
The VSS on the 1990 is only used for the ABS. The engine computer gets its speed signal from the module mounted right on the speedo cable where it goes into the transfercase.
Okay I kinda thought that the VSS was just for the ABS but wasn't sure. I replaced the gear for my speedo a few months ago and I checked the gear last night.
I was talking to another mechanic about my problem and he told me he had the same problem with his truck and it turned out he had something clogged up in the valve body. Could this be the same with mine?
It's possible it might be a valve body issue. The trick will be to figuring out if its the computer not telling the transmission to the shift, or the transmission responding in a very delayed manner.
The transmission has 5 solenoids total, but only two of them actually control what gear its in. If you hooked two test lights up to the wires going to the shift solenoids, you could easily determine if its the computer, or the transmission.
It's possible it might be a valve body issue. The trick will be to figuring out if its the computer not telling the transmission to the shift, or the transmission responding in a very delayed manner.
The transmission has 5 solenoids total, but only two of them actually control what gear its in. If you hooked two test lights up to the wires going to the shift solenoids, you could easily determine if its the computer, or the transmission.
Okay could I do that from the plug on the outside of the passenger side of the transmission or would I have to drop the pan and check from in there?
You can do it from the passenger side connector. Just mind the exhaust pipes. Here's a diagram of the connector. Your best bet will probably be to back stab the connector. They sell dedicated connector "needles" to do this, alternatively you could just use a sewing needle with some wire soldered to it.
The wires of interest are 2 and 3, the shift solenoid wires. These solenoids get constant +12v, and the computer turns them on by grounding them. So you'll want to hook your test lights to +12/positive on one side, and then the other side goes to the shift solenoids.
So there are 4 possible combinations - both solenoids on, both off, solenoid 1 on - solenoid 2 off, and solenoid 1 off - solenoid 2 on. One combination for each gear.
So in 1st, the lights will be in some combination. If you floor it, see the lights change, but the transmission stays in 1st, you know its a transmission or valvebody issue. If the lights don't change, it's an electrical issue.
Also keep in mind that it will normally take the transmission 1-2 seconds to respond to a change in solenoid state.
You can do it from the passenger side connector. Just mind the exhaust pipes. Here's a diagram of the connector. Your best bet will probably be to back stab the connector. They sell dedicated connector "needles" to do this, alternatively you could just use a sewing needle with some wire soldered to it.
The wires of interest are 2 and 3, the shift solenoid wires. These solenoids get constant +12v, and the computer turns them on by grounding them. So you'll want to hook your test lights to +12/positive on one side, and then the other side goes to the shift solenoids.
So there are 4 possible combinations - both solenoids on, both off, solenoid 1 on - solenoid 2 off, and solenoid 1 off - solenoid 2 on. One combination for each gear.
So in 1st, the lights will be in some combination. If you floor it, see the lights change, but the transmission stays in 1st, you know its a transmission or valvebody issue. If the lights don't change, it's an electrical issue.
Also keep in mind that it will normally take the transmission 1-2 seconds to respond to a change in solenoid state.
Thank you for the help! Do I do this test with the truck running?
12-01-2016, 10:35 PM
