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Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 22903
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have a London taxi model tx4 with auto gearbox. I have a

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I have a London taxi model tx4 with auto gearbox. I have a problem with the gearbox when running it from cold.gearbox sensor or selector does not seem to change down from around third gear and the cab stalls. Particularly if I have to come to an abrupt halt.once the cab has warmed up the problem is not so bad but can reoccur if I have to stop suddenly. Can you advise. Most grateful. Stuart.

I'd check all the electrical connections of the gearbox, remove each connector in turn and spray with contact cleaner. Check that the wiring to the gearbox is in good condition with no chafing or frayed wire

If this is OK then check the selector lever linkage / cable under the car for any broken parts and or missing bolts as if this is coming adrift then it can rub on the car body or just bind up

also I've found that if changing the oil helped then its best to do another change once you've done 100 miles or so as you never get all the oil out the 1st drain and fill.

So do that and go from there. If you do still have troubles after that - then the next best move is to let a local Auto Transmission Specialist have a look at it -- they can often repair the unit considerably cheaper than replacement..
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