# Porsche G50 gearbox (1987–1998)

- Source: https://racingcarnetwork.com/wiki/porsche-g50-gearbox/
- Publisher: Racing Car Network (racingcarnetwork.com), the race car marketplace
- Type: gearbox · Brand: Porsche
- Discipline: parts, gt-cup
- Series: one-make-cup, sports-racer
- Era: 1980s
- Last updated: 2026-11-06
- For sale on RCN: https://racingcarnetwork.com/for-sale/porsche-g50-gearbox/ (0 live listings right now)

The G50 is the Getrag-built manual transaxle Porsche fitted to the 911 Carrera 3.2 from 1987, the 964 and, in six-speed form, the 993. Club racers keep it for Porsche-based race cars, and kit-car builders use it behind V8 engines. Its hydraulic clutch, synchronised reverse and wide choice of ratios keep demand high.

## Specifications

| Spec | Value |
|---|---|
| Type | Longitudinal manual transaxle, Porsche design 950, built by Getrag [0] |
| Gears | 5 forward (911 Carrera 3.2 and 964), 6 forward (993) [0][8] |
| Synchromesh | Borg-Warner type single-cone synchros, synchronised reverse [0][12] |
| Torque Rating | 221 lb-ft (about 300 Nm) input rating, as quoted by a Porsche gearbox specialist [0] |
| Ratios | PCA SP911 list for the G50: 1st 12:42 (3.500), 2nd 17:35 (2.059), 3rd 22:31 (1.409), 4th 32:36 (1.125), final drive 9:31 (3.444) [6] |
| Clutch | Hydraulically operated, 240 mm [3] |
| Oil Capacity | 3.6 L in a 964 Carrera 2, 3.8 L in a Carrera 4 [7] |
| Applications | 911 Carrera 3.2, 930 Turbo (1989), 964, 993; Ultima GTR kit cars [0][9] |
| Years | 1987–1998 in rear-engined 911 road cars [0][8] |

## History

Porsche replaced the 915 gearbox with the G50 for the 1987 model year. The new unit was built by Getrag, used Borg-Warner type synchromesh and was rated for 221 lb-ft of input torque [0]. It brought a 240 mm hydraulic clutch [3]. In a 2005 club discussion, one owner put it about 27 lb heavier than the 915 [3]. The same owners agreed it shifts better than a 915 in equal condition [3].

The five-speed box stayed in the 964 from 1989, with 3.6 litres of oil in the Carrera 2 [7]. The 1992 Carrera RS used a G50/10 with closer ratios, steel synchros and an asymmetric limited-slip differential [7]. Forty-five US cars built for a cancelled US Carrera Cup shared that gearbox [7]. The 1989 930 Turbo also got a G50, coded G50/50 [0].

The 993 became the first 911 with a standard six-speed gearbox [8]. Two road versions matter to buyers. The G50/21 carries the shorter ratios, while the G50/20 is the longer box [2]. A Porsche Club GB member reported that US and Swiss cars always had the G50/20, and European cars moved to it during 1996 [2]. The Carrera RS used a G50/31 with modified ratios in the first three gears [8]. Four-wheel-drive 993s use a similar box with a front driveshaft through the nosecone [0].

The G50 kept a second life outside Porsche. The Ultima GTR listed a five-speed Porsche G50 transaxle among its transmissions [9]. One specialist calls the gearbox very reliable and says it often runs about twice the power it was designed for [0]. Specialists such as Guard Transmission and RPM Technik still supply differentials, gears and rebuilds [10][11].

## Palmarès

Not a racing-results machine. The G50/10 served the 1992 964 Carrera RS and 45 US cars built for a cancelled US Carrera Cup [7]. PCA Club Racing still names the G-50 as an allowed transmission for 1987–89 cars in its SP911 class [6].

## What to check before you buy

Read the code stamped on the case and match it to the claimed donor car: The case stamp gives the version and serial, for example G50/20 on a 993 box [14]; ratios differ by version [2]. Confirm whether a limited-slip differential is fitted, and which type: Listings range from open differentials to factory LSD units, and prices follow [12][16][17]. Ask who rebuilt it, when, what was replaced and how many miles since: Sellers quote rebuilds such as 'late 2025' or 'under 600 miles since' without parts lists [12][15]. Ask which gear oil it has run on: Owners link thick oil to cold stiffness and early synchro wear in the G50 [4]. On 1987–89 units, check the clutch release fork and guide tube type: Early parts are superseded, and fitting later ones needs bell housing machining [5]. For club racing, compare the ratios and final drive with your class rules: PCA Stock classes require factory ratios, and SP911 requires a 9:31 final drive with listed G50 gears [6]. Make sure a 993 box is a two-wheel-drive unit if you need one: Four-wheel-drive 993 boxes carry a front driveshaft through the nosecone [0]; RPM Technik offers a 964 4WD-to-2WD conversion [11].

## Did you know

- The 993 was the first 911 with a six-speed gearbox as standard [8].
- Forty-five US 964s built for a cancelled US Carrera Cup used the G50/10 gearbox [7].
- A quoted 5th-gear 80–120 km/h time slowed from 7.0 s to 8.6 s when 1997 993s got taller gearing [18].

## Frequently asked questions

**Which G50 should I look for in a 964 or 993 track car?** For a 964, the G50/03 is the common Carrera 2 box, and the RS G50/10 adds closer ratios and steel synchros. For a 993, the G50/21 has shorter ratios than the G50/20, which suits circuits. Check the case stamp before paying, since the code tells you the ratios.

**How much torque can a G50 take?** One Porsche gearbox specialist quotes an input rating of 221 lb-ft and says the box often runs about twice its design power. Kit cars such as the Ultima GTR used it behind V8 engines. Treat those higher figures as owner experience, not a factory rating, and budget for a strong differential.

**Is a limited-slip differential worth paying for?** For racing, yes. Many road boxes left the factory open, and units with LSD are priced higher. Guard Transmission lists several LSD models for the 1987–89 G50. PCA Stock classes allow any mechanical LSD type that came in a street Porsche, but not a locked differential.

**What does a used or rebuilt G50 cost in 2026?** On RCN in 2026, a used 993 G50/20 was listed at $8,000 and a fresh CMS-built five-speed at $11,500. A rebuilt G50/03 with conversion parts was offered at $6,000. These are asking prices, so ask for rebuild invoices and the parts list before agreeing a figure.

**Can I use a G50 in PCA club racing?** Yes, within class rules. In SP911, 1987–89 cars may run the G-50 with Porsche synchros, a 9:31 final drive and listed gears. Stock classes require factory ratios but allow coolers and street-type LSDs. Prepared classes allow a ring and pinion change.

## Sources

- Porsche transmissions (G50 section) — https://www.lufteknic.com/trans/
- Regear my G50/03 gearbox — https://www.porscheclubgb.com/forum/threads/regear-my-g50-03-gearbox.128235
- Why are the gear ratios on my Varioram 993 so long? — https://www.porscheclubgb.com/forum/threads/why-are-the-gear-ratios-on-my-varioram-993-so-long.133461/latest
- How better is the G50 box? — https://porscheclubgb.com/forum/threads/how-better-is-the-g50-box.97250
- Worn synchro rings — https://www.porscheclubgb.com/forum/threads/worn-synchro-rings.98737/latest
- Clutch — https://www.porscheclubgb.com/forum/threads/clutch.96178/post-208730
- 2026 PCA Club Racing Rule Book — https://pcaclubracing.org/wp-content/uploads/2026/03/2026-PCA-Club-Racing-Rules.pdf
- Porsche 911 (964) — https://en.wikipedia.org/wiki/Porsche_911_(964)
- Porsche 911 (993) — https://en.wikipedia.org/wiki/Porsche_911_(993)
- Ultima GTR — https://en.wikipedia.org/wiki/Ultima_GTR
- Limited Slip Differentials — https://www.guardtransmissionllc.com/products/limited-slip-differentials/
- Porsche gearbox rebuilds and upgrades — https://rpmtechnik.co.uk/?p=865
- Rebuilt Porsche 911 G50 Gearbox — https://www.pcarmarket.com/auction/rebuilt-porsche-911-g50-gearbox/
- Fresh CMS-Built Porsche G50 5-Speed Transaxle (0 Miles) — https://racingcarnetwork.com/race-car/fresh-cms-built-porsche-g50-5-speed-transaxle-0-miles/
- Porsche 993 Carrera G50/20 Manual Gearbox / Transmission G50 — https://racingcarnetwork.com/race-car/porsche-993-carrera-g50-20-manual-gearbox-transmission-g50/
- Porsche G50/03 5-Speed Transaxle & Manual Conversion Components — https://racingcarnetwork.com/race-car/porsche-g50-03-5-speed-transaxle-manual-conversion-components/
- Porsche 964 g50 transmission — https://racingcarnetwork.com/race-car/porsche-964-g50-transmission/
- Porsche G50 transaxle — https://racingcarnetwork.com/race-car/porsche-g50-transaxle/
- Gear ratios — https://www.porscheclubgb.com/forum/threads/gear-ratios.133991/
- Porsche 911 (964): PH Used Buying Guide — https://www.pistonheads.com/news/general/porsche-911-964--ph-used-buying-guide/43438
- G50 help/advice please — https://www.porscheclubgb.com/forum/threads/g50-help-advice-please.97491/latest
- PCA Club Racing Rules — https://pcaclubracing.org/rules/

## Related entries

- Porsche 964 Carrera Cup — https://racingcarnetwork.com/wiki/porsche-964-carrera-cup/
- Porsche 993 Carrera Cup — https://racingcarnetwork.com/wiki/porsche-993-carrera-cup/
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