My 2003, 2.2 Omega had reached 80K miles and was due a major service & cambelt.

Despite the automatic gear box working perfectly, I thought I should get the oil & filters changed as I planned on keeping the car for another 40k miles or so.

I actually printed this topic off and took it to the Vauxhall Main Dealer in Lyndhurst, New Forest and asked if there was an issue with oil specification. They said there was no issue and showed me the service schedule which recommends changing every 40k miles.

The once smooth gear box came back with lumpy & erratic low speed changes. I returned it to the garage and they drove it, and said there was nothing wrong with the changes. I pointed out that I'd been driving the car for the previous 80k miles and was therefore very familiar with its operation, and this was not how it had been the day before the oil change.

They refered me to General Motors DEXRON-VI Global Service-Fill Specification sheet which does state that since 2006, this has been the recommended service fill fluid.

As I explained, this data sheet was of little comfort to me as my once smooth gear box was now irritatingly lumpy. Given that the oil was the only thing which had changed from when the gear box was working perfectly, I requested that they drained the DEXRON-VI and refill it with whatever the original factory fill specification would have been. They said they were unable to do this as Vauxhall now specified DEXRON-VI!

Any further protests from me have been completely ignored, adding great customer service to poor mechanical service!

My advice would be: if it ain't broke, don't fix it, just top the fluid level up as required but don't drain and re-fill!