Gearbox not changing up quick enough??

Hi, My 2007 2.7 RR Sport was driving fine until i lost the brakes and had to replace the servo (brand new unit with the same part number) the car was parked up for 2 weeks while awaiting parts and fixing etc. Now it wont change gear unti over 4k revs, if you put it into command/manual shift all the gears change easily and smoothly. Have i done something daft while changing the servo? or missing something simple? All and any advice appreciated

deangermouse said:

Hi, My 2007 2.7 RR Sport was driving fine until i lost the brakes and had to replace the servo (brand new unit with the same part number) the car was parked up for 2 weeks while awaiting parts and fixing etc. Now it wont change gear unti over 4k revs, if you put it into command/manual shift all the gears change easily and smoothly. Have i done something daft while changing the servo? or missing something simple? All and any advice appreciated

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If it stood for 2 weeks, what was the state of the battery at the end of the 2 weeks I wonder?

Check the brake lights operate correctly, the symptoms suggest there is a fault with the brake pedal switch or one of the bulb filaments has broken and is touching the sidelight filament.

So replaced the brake switch with a spare unit that i had (as suggested by Graculus ) and yes gearbox is now changing properly again. Thanks for all the help, pleased it was a simple fix

Graculus said:

Check the brake lights operate correctly, the symptoms suggest there is a fault with the brake pedal switch or one of the bulb filaments has broken and is touching the sidelight filament.

Click to expand...

Sounds like you were right, can you explain why this is linked please.

J

The early L319's had a configuration where throttle & brake input together was considered implausible, this caused the 'three amigos' + suspension lowering after a few seconds, not great when driving offroad when you need throttle input to keep the TC locked but want to inch along using left-foot braking, the revised calibration was implemented in production mid 2005 and rolled out as part of the 'assurance program' for vehicles already in the wild.
Part of the calibration was to hold the current gear when throttle & brake inputs were seen together (to prevent gearchange causing a change of available torque at the wheels) up to the upper limit the transmission will tolerate before a forced gearchange.

This behaviour can also occur if a broken filament in the tungsten rear lights causes a 12v backfeed into the braking circuit (although this usually throws an engine system or transmission fault on the dash).

The indicator for this in the OP's case was replacement brake booster, it's likely that the brake pedal switch wasn't removed prior to the work, allowing it to over-extend and lose the setting. (it's the usual Ford blue & white NO/NC spring adjust switch that needs to have the position set when fitted), it wouldn't set a DTC as it would be reading 'brake on' on both switches so a plausible signal.

Thank you @Graculus

J