North American Turbocoupe Organization



a4ld overdrive issue
TurboZeke418 Offline
Senior Member
#1
Any ideas on why a newly rebuilt trans...all FoMoCo parts, would stop going into OD and staying there? It will engage into OD, but if I give it the slightest push of the pedal it goes right back to 3rd. It won't stay in OD with a load applied to it. Worked beautifully to this point.
1988 Turbo Coupe, Auto, Loaded everything including leather and Moonroof, 50,300 original miles, garaged since new, MINT condition
1994 Lincoln TownCar- Seafoam Green and beige leather, another beautiful find that couldn't be passed up!
2003 Dodge Durango SLT+ 4x4
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firstsvo Offline
Senior Member
#2
I hate these trannys. I also had mine rebuilt a little while back and have similiar issues. When the car gets hot, won't lock-up. Also like yours, if a fly craps on the gas pedal, it jumps out of OD back to 3rd. It also hops around at certain speeds from 3rd to 2nd or OD to 3rd. Just learned to live with it.
White '88 auto mostly stock, Black '88 5 speed nowhere near stock
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TurboZeke418 Offline
Senior Member
#3
no problems with the trans other than the OD slipping back to 3rd. So smooth you don't even feel the shift.
1988 Turbo Coupe, Auto, Loaded everything including leather and Moonroof, 50,300 original miles, garaged since new, MINT condition
1994 Lincoln TownCar- Seafoam Green and beige leather, another beautiful find that couldn't be passed up!
2003 Dodge Durango SLT+ 4x4
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Jeff K Offline
Administrator
#4
Are you 100% sure it is shifting from OD to 3? How much does the RPM go up? ANy chance it is just unlocking the TCC?
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
11 Crown Vic Interceptor
14 Toyota Camry (wifes car)
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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firstsvo Offline
Senior Member
#5
I was also thinking what Jeff was thinking.
White '88 auto mostly stock, Black '88 5 speed nowhere near stock
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TurboZeke418 Offline
Senior Member
#6
Ok...now i feel really stupid. I think i know....but, what is the TCC? The RPM's only change by about 500-700 rpm. You don't even feel it till its changed. Just slides right into whatever gear or state that its in.
1988 Turbo Coupe, Auto, Loaded everything including leather and Moonroof, 50,300 original miles, garaged since new, MINT condition
1994 Lincoln TownCar- Seafoam Green and beige leather, another beautiful find that couldn't be passed up!
2003 Dodge Durango SLT+ 4x4
Reply

cnpowell Offline
Senior Member
#7
According to one of the symptoms in the service manual, it could be the throttle position sensor needs to be adjusted. The sensor is probably sensing "full-open" throttle when it's not and kicking the tranny down to 3rd. There is an adjustment screw/slot to make the adjustments .... not sure how much to rotate sensor. Mine is doing the same thing .... just haven't had the time to do the adjustment.
Carl
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TurboZeke418 Offline
Senior Member
#8
I adjusted the TPS to the stock specs with a volt meter. Should I have it adjusted differently?
1988 Turbo Coupe, Auto, Loaded everything including leather and Moonroof, 50,300 original miles, garaged since new, MINT condition
1994 Lincoln TownCar- Seafoam Green and beige leather, another beautiful find that couldn't be passed up!
2003 Dodge Durango SLT+ 4x4
Reply

cnpowell Offline
Senior Member
#9
I, believe, it's a mechanical adjustment, not electrical .... loosen the sensor screws and slightly rotate or slide. I'm not sure which direction.
Carl
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TurboZeke418 Offline
Senior Member
#10
hmmmmm ok. its worth the shot. I recently found the correct wiring harness for the trans and when I hooked up the wires for the 3-4 4-3 shift and the clutch convertor solenoid, a few days later it stopped staying in OD. W/O the wires hooked up it worked fine. But, now I disconnected them and it still has the problem.
1988 Turbo Coupe, Auto, Loaded everything including leather and Moonroof, 50,300 original miles, garaged since new, MINT condition
1994 Lincoln TownCar- Seafoam Green and beige leather, another beautiful find that couldn't be passed up!
2003 Dodge Durango SLT+ 4x4
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