Like the engines, the 987 gearbox story splits cleanly by era.
Manual (both eras)
Both the 987.1 and 987.2 offered a 6-speed manual transaxle. Because the transaxle integrates the differential, a single 75W-90 (GL-5) gear-oil fill (about 2.8 L on refill) covers both — there is no separate diff service. The hydraulic clutch shares the brake reservoir and DOT 4 fluid, so it is bled during the regular 2-year brake flush. Earlier 987.1 cars used a plastic clutch slave cylinder that can crack; Porsche updated it to a metal unit.
Tiptronic S (987.1 only)
The 987.1 automatic is the 5-speed Tiptronic S, a ZF 5HP19 torque-converter unit. It uses Pentosin ATF-1 / ZF Lifeguard 5. Porsche calls the fluid "fill-for-life," but specialists strongly recommend servicing it every 4-6 years; a drain-and-fill only exchanges about 3.5 L of the ~9 L total because the converter retains the rest. The final drive is separate (about 0.8 L of 75W-90). Worn valve-body bores cause harsh, delayed shifts as these age.
PDK (987.2 only)
The 987.2 replaced Tiptronic with the 7-speed PDK dual-clutch. It has two separate fluid circuits: a 75W-90 gear oil (about 2.95 L per service) and a Pentosin FFL-3 clutch/control fluid (often mislabeled "PDK transmission fluid"), which requires a PIWIS temperature-controlled fill. The gearset is robust; the Mechatronic control unit and its sensors are the concern, so regular fluid service (many specialists do it around 40k miles) is the best protection.
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