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Discussion Starter #1
I have just acquired a 320D automatic. I find the car generally frugal, especially on long journeys, comfortable and great to drive. Can anyone out there explain to me the strategy for the automatic transmission torque convertor lock-up? The transmission t/c lock-up will only activate when the car is at a speed of 64ish MPH, this seems high to me and is only an advantage on the motorway, could there be a fault? Common sense would be to use the transmission t/c lock-up in more of its five gears over a range of throttle positions.
I previously owned a Audi A4 auto and its transmission t/c lock-up would activate in 3rd and 4th gear making it more relaxed to drive and a little more economical.
PS I have read the owners handbook and trawled the internet but can't find an explanation, I am a time served mechanic so I have a good knowledge and understanding of most things that have cogs, gears and pistons.
All explanations greatly accepted.
 

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Discussion Starter #3
Thanks Ronnie, Still looking myself and I now think that there is probably a progaming problem; it could be a visit to the nearest dealer.
 

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Have you thought of having the codes read for the gearbox? it may come up with something as there are many sensors and solenoids in the box
 

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Discussion Starter #5
Yeah Ronnie, Going to book it into the nearest BMW garage to get the codes read and re-program the auto control box if possible, will keep you informed. I have since been told that the lock-up clutch should be applied in 3rd 4th and 5th gear, 5th gear locking up at 55mph so there's definately something gone wrong.
 
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