Taper roller bearing. Porsche 911 / 912 / 914 / 930 / 964 / 993 / 924 / 928

Rear left and right differential carrier bearing.
This tapered roller bearing, also known as a differential carrier bearing, is used in the rear output assemblies of the differential and manual transmission on various classic Porsche models. Engineered as a precise OE replacement, it meets the original Porsche specifications for dimensions, load capacity, and tolerance. The bearing installs directly without modification, restoring proper carrier alignment, support, and smooth drivetrain operation.
Sold individually.

Fits:
Porsche 911 1969-1971 * with magnesium pressure cast housing
Porsche 911 1972 - 1989
Porsche 912 1969 * with magnesium pressure cast housing
Porsche 912E 1976
Porsche 914 1970 - 1976
Porsche 930 Turbo 1976-1989
Porsche 911 (964) C2 1989 - 1994 (rear right only)
Porsche 911 (964) Turbo 1990 - 1994 (rear right only)
Porsche 911 (993) 1995 - 1998 (rear right only)
Porsche 924 1976 - 1985
Porsche 928 1978 - 1995

Diagram ref no 8

•  Function: This bearing supports and aligns the differential carrier or manual transmission rear output shaft, allowing smooth rotation under load and controlling radial/axial movement of the carrier assembly. It ensures the differential or transmission output runs true, quietly and with minimal friction.

•  Position on Car: Usually located in the manual transmission/differential rear housing (for example in the rear of the 911 manual gearbox, or the transaxle/differential carrier area). It may serve as the bearing between the carrier housing and the output shaft or differential ring-gear carrier.

•  This part is critical for proper gear meshing, quiet running, bearing life and overall driveline integrity.

With age and use, the bearing can develop wear in its rollers/races, looseness, noise, increased friction, or misalignment. A worn bearing may lead to drivetrain noise, vibration, premature gear or bearing damage, loss of efficiency, or catastrophic failure. The bearing supports the differential carrier output shaft – incorrect bearing performance can result in excessive play, wobble, and stress on neighbouring components.

When to Replace:
•  During a differential or transmission rebuild, where the carrier, output shafts or bearings are being replaced — it’s best practice to install new bearings.
•  If you detect noise (growl, whine, hum) coming from the rear differential or output area, particularly under load or at higher speed. If there is measurable play / movement in the differential carrier or abnormal backlash in the gearset. If you notice metal debris, “bearing-noise” or vibration emanating from the drivetrain output / differential area. 

•  When you upgrade or service the manual transmission/differential – matching new components with new bearings ensures optimum alignment, longevity and performance.

Replacing this bearing means you restore correct support and alignment, minimise noise, protect the differential and improve durability. This part is critical for proper gear meshing, quiet running, bearing life and overall driveline integrity.

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

99905902702

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