Shifting Problem Under WOT
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Shifting Problem Under WOT
Just picked up my first powerstroke. 96 F250 Automatic. Runs great besides a fuel leak and the transmission slipping. The truck drives great until I get into it. It feels like it slips into neutral when I full throttle it. I had a little bit of hunting between gears at med throttle (until I did the tc lockup switch). Turbo spools up fine after 2k rpms. Fuel leak is somewhere under the turbo or I think the lift pump in front of the turbo. Fuel wouldn't effect the trans shifting into neutral would it? Kick *** truck btw
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I replaced the throttle pedal sensor which was a little out of spec. Checked wires to pcm but cant find a problem. The solus pro finds power but wont communicate with the pcm. My can scanner has the right protocol and connects. It reads check engine light on no codes. My cel flashes on for a split second when i turn the key forward but doesn't come on when I'm driving.
Frmr Ford Trans Engr
Joined: Aug 1999
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From: SE Florida
How did you check them? Visually? That isn't worth your time. Did you check for opens and shorts from one end of each wire to the PCM with a meter? That's the only way to check wiring that's worth spending any time.
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Where can I find a wire diagram for the pcm to diagnostic link? I just inspected the harness for damage, bends and contamination. I'm not sure if its our scan tools or the pcm. Overdrive button on the column is damaged. Could that cause the trans to slip or go in to neutral? Thanks in advance
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I replaced all the trans oil and filter. It was dirty but not too bad or burnt. Some metallic specs in the oil. Small tiny particles that the magnet couldnt collect. (magnet was full truck has over 300k miles). The fluid still looks clean after 300+ miles and I got on it hard more than a few times. The fluid is red and dosnt smell burnt but there is dark dirt specks in the trans oil when you put it on white paper. Dirt left over from the drain and fill? I drained the converter but couldn't get the last bit of old oil from the cooler... could that be the dark spots (the spots are like dirty oil not particles). Is red trans oil a good sign?
Hotshot
Joined: Dec 2005
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From: evansville in
Does it not pull or kind of hang at high rpm and sort of get lost as to weather shift or not? by torque converter switch u mean a manual over ride?
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Hotshot
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From: evansville in
Wiring diagrams are at the top in tech/mod links. not sure but if anywhere will a diag chart will b there.
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If I give it full throttle it revs all the way up quick with no resistance. If I let off the pedal it will shift back into gear. It will not downshift at all. It feels like it shifted into neutral. At half throttle it will shift back and forth between gears several times and than upshift. If I give it more than half throttle it will powershift into the next gear and give me a good pull forward as it shifts up. Any more than that and it goes into neutral. Yes manual over ride switch. Trans shifts quicker with converter locked but still goes into neutral or a complete slip at full throttle or right about full throttle. When it slips the engine revs up until I let off the pedal.
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I looked a couple of times. I'm not seeing anything. Maybe I'm missing something?
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Update. I checked fuel pressure it was bouncing from 35 to 85 up and down at idle. I fixed the fuel leak. Turned out to be the fuel pump itself. After I changed the pump I was not able to get the transmission to slip. I got better shifts due to the extra power the truck had at the shift point and it no longer goes into neutral when I push it. So low fuel pressure causes the trans to go into neutral. Anyone else ran into this before? Could the engine still rev all the way up with zero power to move the truck? I called the stealership yesterday they swear my truck is obd2. Build date is 06/96. Still can't communicate with pcm. Anyone know where I can download the repair manual for this truck?
Frmr Ford Trans Engr
Joined: Aug 1999
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From: SE Florida
I don't know if you can download the manual here, but you can buy one. Service Manuals, Owner Manuals, Wiring Diagrams, Service Bulletins - Helm Incorporated
Engine problems can cause all sorts of transmission problems. What you had is not unusual when the engine isn't right.
Engine problems can cause all sorts of transmission problems. What you had is not unusual when the engine isn't right.
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