Citroen C5 auto issue

[Quackers]

Never had an auto have issues before so it's all new to me, 2007 6 speed C5 (2.2 hid 173bhp). On way home after the car had been running 20 mins the car starting doing big thuds going down the lower gears , from 3rd to second and second to 1st. It also felt like it was slipping a few times going up between 2nd and 3rd. The thud also happens engaging reverse . It's on 158,000 miles now , last gearbox oil change 20,000 miles ago.

Does this sound like its going to be expensive ? Or is it the symptoms of something simple like low on gearbox oil ?

[xantia_v6]

I am not familiar with that particular transmission (although it could be the same one as in our recently acquired 308 THP 156), but on the 4HP20, clunky changes, especially into reverse, are a sign that the transmission ECU has detected a fault and gone into limp mode, using mainly hydraulic, not electronic control of the transmission.

I would advise connecting a Lexia ASAP and reading the fault codes.

[Quackers]

Thanks for the reply, just started my engine again and engaged reverse and it was smooth so does sound like you say, detected an error then went into gearbox type of limpmode