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Mechanic Martyn
Mechanic Martyn, Australia Car Mechanic
Category: Australia Car
Satisfied Customers: 1002
Experience:  Advanced trade certificate in Automotive engineering
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Ford EF I have a EF Falcon with an auto transmission and recently

Customer Question

I have a EF Falcon with an auto transmission and recently replaced the break booster. shortly after that it stopped going into top gear and soon after that will only change up at about 4,000 RPM. I have changed the gearbox and the problem remains. Any suggestions or help Please.
Submitted: 6 years ago.
Category: Australia Car
Expert:  Curtis replied 6 years ago.
Has the one way valve on the booster been replaced, is the valve working correctly, is there another air leak. You will need to check these as it will cause these symptoms.
Customer: replied 6 years ago.
I have checked all the suggested areas and can not find any air leaks and all valves appear to be working correctrly.
regards Geoff (Does the computer play any part in the gearbox shift function?)
Expert:  Mechanic Martyn replied 6 years ago.

Hello and welcome to Just Answer

There are two things on the EF that cause this

1. is the inhibitor switch or gear position switch - it tells the computer what gear you are in as well as preventing starting in gear. If it is faulty the ecu doesn't know what to do.

2. Is the Throttle position switch, if this is faulty the computer drops into kickdown and flares the engine or drops into limp mode.

Thats the most common causes in my experience. I imagine the new gearbox came with a gear position switch fitted so I'd go for the throttle position switch (TPS)


Mechanic Martyn

Mechanic Martyn, Australia Car Mechanic
Category: Australia Car
Satisfied Customers: 1002
Experience: Advanced trade certificate in Automotive engineering
Mechanic Martyn and other Australia Car Specialists are ready to help you
Customer: replied 6 years ago.
Thank You. Your information was helpfull. In the process of checking things I have found that the changing up at high reves was caused by the econ/powere button being moved to the power position. I now believe that changes are happening correctly although a little more chuncky that I remember. I am of the opinion that it is stil NOT going into top (4th).
Expert:  Mechanic Martyn replied 6 years ago.

Hello again

4000 rpm is still very high even with the power option in.

I have an EF and an AU and worked on countless falcons. I have never experienced gear changes that high unless the throttle was very hard depressed.

If you are only on half throttle the changes should occur much earlier.

This may get better with a bit of driving with one driver as the computer learns the driving style of that driver.

After the gearbox change it will be a relearn but this usually takes only around 30 to 50kms.


Mechanic Martyn

Customer: replied 6 years ago.
Additional information that I gathered today while driving. The gearbox doesn't "drop down" when you plant your foot such as for overtaking. it almost apears as if it is locked into kickdown mode permantly
Expert:  Mechanic Martyn replied 6 years ago.

Ok this usually indicates a problem with the information getting from the TPS to the ecu and down to the transmission. It can be a TPS (throttle position switch) problem.

In which case remove the wiring plug on the TPS and spray the contacts with a contact cleaner - this may help but if the TPS is faulty it will need replacing.

OR - It could be an ECU problem - can be replacd with a second hand one but ...

TRY checking the harness down to the gearbox, give every connection a wriggle and a open and clean, a loss of even a tiny voltage over a dirty connection can cause problems.

Check that plug into the gearshift position switch again.

Try going for a drive with the TPS disconnected if its the same then that will be the cause. Under $100 on ebay.


Mechanic Martyn