All manual-transmission MGF and MG TF models use the Rover PG1 five-speed gearbox, a compact transaxle mounted directly to the rear of the transversely-installed K-series engine. The PG1 incorporates the gear set, final drive, and differential within a single casing. The PG1 was used across a wide range of Rover Group vehicles (200/25, 400/45, 75, and others), so many internal components are shared across the group, aiding parts availability, though the final drive ratio and some external fittings are specific to the MGF/TF installation.
Two Final Drive Ratios
The fundamental ordering decision for PG1 components is the final drive ratio. The MGF 1.8i and MGF 1.6i use a 3.9:1 final drive ratio, producing relaxed cruising at motorway speeds and well-spaced in-gear increments. The MGF VVC, Trophy 160, MG TF 135, and MG TF 160 use a shorter 4.2:1 final drive ratio, which matches the higher-output engines' power band and produces livelier in-gear acceleration at the cost of marginally higher engine speeds at cruising. The two final-drive specifications share the same internal gear ratios (1st through 5th, reverse), the difference is purely the final drive gear pair.
Gearbox service items at the internal level often need to be matched to the final drive specification, so confirm engine variant when ordering.
Steptronic and Stepspeed, The ZF CVT Automatic
The automatic option on the MGF and MG TF is a ZF continuously variable transmission (CVT) marketed as Steptronic on MGFs from the MY2000 facelift and rebranded as Stepspeed on the MG TF (and on later MGFs) after BMW retained the Steptronic name following its disposal of Rover. The CVT is only available on the 1.8-litre 120 PS non-VVC engine, it was never offered on the 1.6-litre, on VVC engines, or on the MG TF 135 or TF 160. The CVT provides continuously-variable ratio selection in fully automatic mode, with six pre-set 'manual' ratios selectable via steering wheel-mounted push buttons or the centre-console gear lever, the 'flappy paddle' feel we discussed under the parent Drivetrain node. CVT service is materially different from manual gearbox service: the unit has specific CVT fluid that is not interchangeable with conventional automatic transmission fluid, the pressure circuits are complex, and most internal work is beyond the scope of generalist workshops.
For this reason, the Automatic Gearbox child page carries the external and internal service items in a single combined listing rather than splitting them as the manual gearbox sections do.
Catalogue Structure, Three Child Pages
This section divides into three child pages reflecting what can be serviced at different levels of workshop capability. External - Manual Gearbox carries items accessible without opening the gearbox casing, the gear selector mechanism and cables, linkage components, oil seals at the driveshaft interfaces, the speedometer drive, the reverse light switch, and the gearbox breather. These are the items that a competent home mechanic or general workshop can service. Internal - Manual Gearbox carries the gear set, shaft bearings, synchromesh rings and components, detent mechanisms, and internal shims, items requiring gearbox disassembly and correspondingly more specialist equipment and experience.
External & Internal - Automatic Gearbox combines all Stepspeed/Steptronic CVT service parts in a single page, covering external service items (filter, dipstick, oil seals) alongside internal service items that are essentially specialist-only.
Ordering Guidance
For vague or notchy gear selection, worn synchromesh, or gearstick feel issues, the first inspection should be the external linkage and cables, most 'gearbox' complaints on MGF and MG TF cars are actually external-linkage issues that can be resolved without opening the gearbox. The External - Manual Gearbox page carries the relevant parts. For genuine internal gearbox faults, grinding synchro on second gear (the most common internal failure), whining bearings at specific speeds, or seized selector forks, the Internal - Manual Gearbox page carries the rebuild parts, though this work is almost always sent to a specialist gearbox rebuilder. For automatic gearbox issues, slipping, harsh shifts, or warning lights, the Automatic Gearbox page carries the service items, but serious internal faults should be assessed by a CVT specialist before parts are ordered, because not all CVT faults are parts-replacement-appropriate.
In all cases, confirm the final drive ratio (3.9:1 or 4.2:1) and, for automatics, the specific CVT generation on the car.