The Rover PG1 gearbox fitted to the K series including KV6, L, T and M series engine was manufactured by Powertrain Limited (who have now ceased trading), is a five-speed constant mesh gearbox, which employs helical gears for speed transmission and final drive. The transmission castings are full aluminium construction and all other components optimised for improved weight (36kg dry). The gearbox can be supplied with either a standard open differential or a Limited Slip Differential.

Due to the modular design of the gearbox various final drive ratio and 1st to 5th gear ratio combinations have been used. Including both present and past an overall total of 21 ratio combinations, 5 speedometer gear ratios; and 7 clutch levers designs for both hydraulic and cable operation can be called on to ensure the customers requirements are met.

The cars these were fitted to were the Rover and MG Maestro, Montego in 1600cc up, MGF and TF, Rover 200, 25, 400, 45, 600 and 800 plus the MG ZR or ZS in models fitted with engines 1796cc upwards. The Lotus Elise with the Rover K series engine also used the PG1.

The PG1 gearbox is very robust and versatile. It is popular due to the variations that the factory gear sets use which can be adapted to suit a customers requirements. There are also aftermarket gear kits and final drives available if the factory gear sets do not meet your requirement. Rover supplied some of the more powerful models with a Limited Slip Differential. Two types were used. A Torsen type A was fitted in to the Rover 220 turbo (Tomcat). The Torsen type B was fitted into a Rover 620 Ti, Rover 820 Vittesse or a Rover 218 BRM.

Most normally aspirated (NASP) cars use the standard PG1. The stronger U spec (uprated) version is used on the high torque engines which include all turbo (including diesel) models plus the KV6.