I have the same car, and have done a drain and refill. so please follow very carfully.
There are No work-shop manuals around for the V6 Vectra in print.
The dip-stick is very near the battery and is a black lever which is very stiff to use and is in a very tight space you need to lift it out and up, and then remove the dip-stick just like the engine oil one.
When cold 30oC or below use the bottom temp marks on the dip-stick, when above 30oC use the top temp marks after about 3 mins running your engine.
You put the ATF Dextron II oil down the dip-stick pipe with a small and very clean funnel a little at a time, I did use a proper "oil safe" contaner and pump which i bought from Demon Tweeks.com to do the job, for better access you can remove your battery like I did with mine,I also used my jump leads to start the car to check the levels, but do keep checking the level oftern or you will over fill it, When you start the car put you foot on the brake and move the gear shift up and down through the gears and then back into park. "OVER FILL" and if you do that you will have to remove the excess down to the top (bottom) oil marker if it is cold! or the top (top) oil marker if it is hot! or you will damage it if you do not. (again I did have a "sealey" fluid vacume pump) from D.T.com just in case!
If you have any questions go to or phone a Vauxhall dealer and ask!! most will help you, if you are nice to them!!!!
Good luck and take your time and make shure you have every thing before you start and KEEP IT CLEAN at all times!
V6 Tim, May 2007
