96 crown vic won't shift above 2nd

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brother in law's car. Don't know yet if any codes present etc but will can when I see it. Just got the car on the road after sitting a year, after he bought it. (I don't know if he ever test drove it and it worked then or...) He was thinking the MLPS sensor (Shift Lever Position) after a clerk at advance auto suggested it. And it makes a little sense to me! I don't know fords... any clues appreciated.
 

eljefino

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That's on the to-do list when I'm under there looking for corrosion on that MLPS switch.
 
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snowblind in TX
MLP sensor is my first thought as well. Pay attention to the alignment marks if/when you replace it. If you can, pull codes first. MLPs usually don't code unlike other trans electrical components, so a shifting problem with no codes indicate a suspect MLP. A scan tool with data function can find a bad MLP in a heartbeat.
 

eljefino

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Back from the diagnostics & test drive: Will hold 2nd until 50 MPH then when feathering the gas to try for an upshift goes into neutral. One regains traction by going for manual 2nd, but then it's 2nd "with engine braking" and a more irritating ride. Both the MLPS switch and the other 8-ish pin harness are free of corrosion. Didn't ohm out the MLPS switch b/c it's tight and rusty in there. Put the scan tool on and it reports 20% throttle at idle, odd. Also 48'C coolant temp when it was "stone cold"; I ask did you have it running, he says "not for a couple hours" Has (only) codes for misfires on cyl 2,3,4 and some jerk disabled the check engine light... not even on with KOEO. It does miss and I'm after him to get new plug wires b/c the ones he's got don't snap on all that positively. So what say ye now? Maybe a bad solenoid pack? I've never dropped a trans pan but the pictures online look relatively straightforward...
 
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 Quote:
Will hold 2nd until 50 MPH then when feathering the gas to try for an upshift goes into neutral. One regains traction by going for manual 2nd, but then it's 2nd "with engine braking" and a more irritating ride.
Is the 1-2 shift at normal speed? Why did you stop @ 50mph? What happens if you don't feather foot it seeking an upshift? You're saying that it definitely goes into neutral ..and at that point you can free rev up to WOT with absolutely NO power transmitted to the rear wheels? Just looking for holes in the road test diagnostic.
 

eljefino

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^ What's your level of confidence on that? Have read of "mystery neutrals" but they usually happen to someone who was just cruising along in overdrive.
 
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snowblind in TX
Your tech has a scan tool/data link? Yes? See what the MLP PID reads when you manually go through the gears. Thats it. It's not rocket science. If the data doesn't match lever position or flicks between readings with the lever in a certain position then you have MLP problems. Its not an intermittent problem so if there is a problem it will make itself known.
 

eljefino

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^ LOL my tech is me and my generic scan tool doesn't do tranny stuff. Wish it did. ;\) Ever changed one? Come out okay? Bolt heads are pretty rusty.
 
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snowblind in TX
Well, I worked in a Ford dealership for 11 or so years (engine performance/electrical), and I did change a few. Put car in neutral, remove bolts (8mm/5/16), slide switch straight off, verify marks line up on new switch, slide on and install bolts. Try not to move switch around and throw alignment off during install. There is an alignment tool for that switch to use during install, but our trans guy lost it and we never bothered to get another one so it really isn't essential. Even a generic scan tool should be able to pull MLP data as there isn't a separate TCM on that model, all trans functions are controlled by the PCM and should be accessible by any generic scanner.
 
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