Hello Juddy,Re your V30 trencher,the 30 stands for 30 H.P. V4 aircooled Wisconsin engine although some were retro fitted with Holden motors, skid steer with a swivelling front axle to allow for very slight changes of direction when trenching.Normal drive is through a manual gearbox but when trenching a hydraulic motor is used for movement and the manual drive is used to power the digging chain to give a range of chain speeds to suit varying soil types.The hydraulic drive allows for the very slow speeds necessary when trenching.A company called Mole engineering were the agents 30 plus years ago and maybe still are.Thats all I can remember BISTBC Regards John