3.0 cdti auto box misbehaving

**Davethemover** · 14th June 2008, 20:03

I have an 07 signum 3.0 cdti auto doing strange things whilst changing.
1-2, 2-3, 3-4 (less as going up the box) I get an increase in revs (sometimes as much as 800rpm) and the engine free wheels before dropping into the next gear. Often, the revs drop in two stages, giving warning of a big wang in revs coming (if you've experienced it, you'll know what I mean). Worse when cold but detectable still when warm. Apparently caused by a malfunctioning valve in the box.

Dealer has changed the box under GM warranty but its still doing it but with a smaller rev increase. Its also now occasionally clonking when changing before giving an xtra big wang in revs.

Anyone out there had the same thing or got any ideas ?

Cheers, Dave.

Any clues to

**Gsi3.2** · 14th June 2008, 21:40

back to the dealers..

...thats the best advice i can give..

**Davethemover** · 15th June 2008, 16:25

Absolutely - I'm not touching it ! But the more knowledge and info I have, paticularly about other Signums/Vectras with the same problem, the better when talking to the dealer.

Cheers,

Dave.

**KeefyJ** · 16th June 2008, 14:51

Agree - back to the dealer.

Mine is same train and does not do this but does function very differently when cold as against hot and also when being driven "gently" does odd things against "normal"

driving. Only done 2700 miles so far so still getting used to it but will look out for your experience.

**KeefyJ** · 2nd July 2008, 17:19

Wondered how you got on at the dealer?

Been watching mine more closely and have still not noticed the jump in revs on change you experienced but have noted that at the same speed in the same gear it uses slightly different revs (e.g. in a 30 it holds 3rd normally at about 1500 BUT will lift to about 1800 and then feather back (2nd seems to need about 2000 at the same speed) ALSO AND MORE NOTICEABLY one extra click on cruise and it will drop to 4th at about 32 mph and pull just over 1000 rpm BUT will then show 1400 and fall back down again without a change.

Isn't it annoying too (well it is for me as a driver who was taught to use gears to balance speed against road :

) that just as you approach a junction or roundabout the drive disengages and revs drop to 800 leaving you to have to brake instaed of the engine slowing the car.