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Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 22893
Experience:  BEng hons Mech engineering, in auto industry 22 years
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, I have a Citroen C4 2007 1.6 petrol with automatic gearbox,

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Hello, I have a Citroen C4 2007 1.6 petrol with automatic gearbox, the fully automatic one with park position and manual shift options, plus the sport button. I have this car for close to 2 months already, bought it second hand at 47k miles.
The car is more or less OK, I have this concern that often it changes gears when accelerating , from 1st to 2nd and from 2nd to 3rd , with abrupt vibration, call it vibration or a light jolt. I observe it makes it more often when cold and right after start. Looks like when heats up a little bit this changing improves or the issues disappear. Looks like the issue is observed when I am not giving it enough power in low revs. Apart from what I described there is no noise, nor grinding, nor shift taking out etc. Only this abrupt vibration when changing. I have been driving VW DSG automatics last years, never had such experience. Years ago I used to drive manual, the issue I described feel pretty much like if you drive a manual shift and want to change to upper gear, but dont give it enough power and release the clutch pedal too quick, it is just the same feel.

1st thing I'd checkis for worn mountings - check the tightness of the engine and gearbox mounts and their condition - this is best done by using a jack to take the weight of the engine off the mounts and seeing if any cracks or splits open up in the rubber.Also check the tightness of the mounts bolts

if thats OK then
I'd take a look at the colour of the transmission oil it should be a dark red colour if its black then its needs changing together with its oil filter. Also check its level with the gearbox warm and just after you've moved the selector through all the positions leaving it for a few seconds in each one and then back to park.

You can top up the box through the side fill plug if required and make sure you use the correct oil for your car as the fluids are not all the same. Some manufacturers recommended a change of the type of fluid - Speak to the local dealer and parts dept - they will advise you on the updated fluid to use..

If that’s all OK then 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

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