some manufacturers say a gearbox is a topup only affair , personaly ive always changed or found a way to change the gear oil every 2 years or 24000 miles wichever comes first , its GOOD PRACTICE , if ther aint a drain plug try siphoning out the oil just after a run so its thinner/ maybe some sort of thin pipe and a syringe to suk it out. g.l. lee
lee, April 2007