i have a octy 1.8 auto and in the last week or so there has been excessive noise whilst driving over about 25mph, as it sounds like i'm revving really hard, even though i'm not. i have been told this maybe a gearbox problem?? also i need to change my drivers side front wheel bearing, but would this make such a noise? if anyone has any ideas what this could be that would be great, and how i could fix it!!! thanks guys.

Is the engine revving higher than it used to for a given road speed and gear? I've several ideas about the most likely cause, and this will narrow it down.

the car doesn't seem to be revving any higher given the speed, and because its an auto i cant really tell for the gears! but i dont think its revving higher to be honest.

First port of call then, and it's way cheaper than an exchange gearbox, is to get the transmission fluid changed. Get a garage to do it (it's worth the money, as anyone who's ever smelt used TQF fill tell you).

**** you reckon its the gear box? i was hoping its only the wheel bearings and have it booked it to get it changed tomorrow! (Wednesday). i hope that sorts it, will let you know. if not i'll get the transmission fluid changed right away.

I've never heard an Octy wheel bearing, but anything I've heard bearings in, it's a very distinct squeal. Is it better or worse when you're turning at steady speed, and does it get better when you brake?

The TQF change will sort all sorts of apparent auto box problems. Ok, so would an exchange box, but as often as not it's not needed; the old TQF is causing the problem, so change that and it's sorted.

got the bearing done today and so far so good, the noise has gone! hopefully the gearbox is ok then?

I'd say so, but if the mileage is over 50_000, I'd have the transmission oil changed anyway. You'll not find it in any manufacturer's schedule that I know of, but ZF recommend changing transmission fluid on their autos every 50_000.