Hi all, Time to throw myself on your expertise please! I have an early 2004 Focus Petrol 1.8i with a Manual gearbox., It's done a 150k miles so trying to look after it as it's in such good condition, I turned to thinking about an oil change for the gearbox. Haynes Manual states there's no Oil Drain Plug - and as I do not own a syphon- or want to disturb a drive shaft - I asked a mainly Vauxhall garage friend what might be done.
He claimed that there was, in fact, a drain plug below the filler plug, but it wouldn't drain all the oil as it was rather highly situated.

I managed to 'start' the 1/2" plug easily, but then it just spun without unscrewing any further, and - a big worrying 'AND' - I cannot get it to screw back up again!!.
I have test driven the car and there's no oil leakage at all - but naturally I wonder if at some point it might lose the contents whilst driving with dire consequences!

ANY advice as to what this apparent 'plug' might be would be very welcome, and although I really don't think I have stripped the thread on it (I did not use much force at all), what does one do in such a situation?

Over to the experts?, Cheers, Richard