Porsche 911/01 5-Speed Transaxle

In the Porsche community, the 911/01 transaxle is a specific 5-speed gearbox used in the 1970 and 1971 Porsche 911 (C and D Series). It is the final and most refined evolution of the original Type 901 family before Porsche moved to the larger, heavier Type 915 in 1972.

Listing Details

• Porsche 911/01 Transaxle
• Five-Speed Manual Dogleg
• Removed from 1971 911T
• Serial #7110799

While it shares the same “dog-leg” shift pattern as the early 901, it features critical structural and mechanical changes.

1. Key Technical Specifications

The 911/01 is often called the “Magnesium 901” because it transitioned from the heavy aluminum casing of the early cars to a lightweight magnesium alloy.

• Case Material: Magnesium (lighter but more prone to corrosion/stripping).

• Shift Pattern: “Dog-leg” (1st gear is left and down; 2nd through 5th are in a standard H-pattern).

• Clutch Type: Pull-type clutch (225mm). This is a major departure from the “push-type” (200mm/215mm) used in 1969 and earlier.

• Gear Ratios (Stock): * 1st: 3.091 (A)

  • 2nd: 1.778 (GA)

  • 3rd: 1.217 (O)

  • 4th: 0.926 (V)

  • 5th: 0.759 (ZA)

  • Final Drive: 4.43 (7:31 Ring and Pinion)

2. The 911/01 vs. Early 901 Transaxles

If you are looking at a 1970–71 911, here is how the 911/01 differs from the earlier boxes:

3. Common Weaknesses & Issues

The 911/01 is a delight to shift when healthy, but it has a few known “Achilles’ heels”:

• The “Simplified Differential”: Early 911/01 units used a differential pin design that was prone to failure. If the pin shears, it can punch a hole through the side of the magnesium case. Most survivors have been retrofitted with the “Update Kit” (sturdier bolts/pins).

• Intermediate Plate Wear: The magnesium case is softer than aluminum. Over time, the bearings can “walk” or vibrate, creating play in the intermediate plate. Many builders install an aluminum intermediate plate from a 914 during a rebuild for added strength.

• Synchro Wear: Like all 901-series boxes, the Porsche-style synchros are slow. Rushing the 1-2 or 2-3 shift will lead to grinding and expensive “dog teeth” replacement.

4. Why Enthusiasts Love Them

Despite being less robust than the later 915 transaxle, the 911/01 is the preferred choice for “Hot Rod” builds (like 2.0L or 2.2L S-spec cars) for two reasons:

1. Shift Quality: The 901/911 family has a more precise, mechanical “bolt-action” feel than the often-vague 915.

2. Weight: It is the lightest 5-speed transaxle Porsche ever put in a 911, making it perfect for lightweight, high-revving builds.

Buying Tip: If you find a 911/01 for sale, check the bottom of the case for the stamping. It should read 911/01 followed by a serial number. If you see 914/01, that is a mid-engine version with the ring and pinion “flipped”—it will have 5 reverse gears and 1 forward gear if bolted into a 911 without modification!