Well folks - I did bring it in after all. Now 198k miles on the odometer. I've had the belts changed a year ago. I replaced all the engine mounts myself a few months ago - quite a learning curve for a non-mechanic! Bit of roughness in the gearbox now so taking more interest in that.
The transmission fluid has never been changed to my knowledge. I'll try and do a few flushes as a first step. What local (oz) product do I use?
And where do I find the model number of the gearbox?
I know it's a silly question, but would there be a spare gearbox in good condition be knocking around in Oz?