The Getrag F25 manual transmission was fitted to many vehicles in the European Opel production line-up including the Opel Calibra.
It is a five-speed transmission with the following configuration: There have been many references to the numbering designation that Opel elected to utilise for gearboxes; one of the more common arguments is that it refers to the ft·lbf torque capacity of the gearbox, in this case being a 250 lb⋅ft (339 N⋅m) torque limit.
Other arguments include that it is simply related to the engine size (the F25 gearbox was often fitted to 2.5-litre engine vehicles).
This argument, that engine size is the justification for the numbering, could be disputed as the Opel Vectra B with the 2.6-litre V6 engine was fitted with an F23 transmission.
The numerical designations usually indicate the maximum torque rating of the gearbox in newton metres.