Differential outer bearing, Left. Porsche 911 / 964 / 993 / 986 Boxster / 996 / 997 / 968  ❭  99905906400

Differential outer bearing, Left. 50 x 90 x 21.7
This OE Match differential outer bearing is a replacement left-side differential bearing for selected Porsche 911, 964, 993, 986 Boxster, 996, 997, and 968 models. It is designed to match the original-style fitment and function, helping support correct differential operation and drivetrain reliability.

Fits:
Porsche 911 1987 - 1989
Porsche 911 Turbo 1975 - 1989
Porsche 968 1992 - 1995
Porsche 964 C2 / C4 1989 - 1994
Porsche 993 C2 1994 - 1998
Porsche 986 Boxster S 2000 - 2004
Porsche 996 C2 / C4 1998 - 2005
Porsche 996 Turbo GT2 2001 - 2005
Porsche 996 GT3 2000 - 2005
Porsche 997.1 Turbo / GT2 / GT2 RS 2007 - 2009
Porsche 997.2 GT2 RS 2011
Porsche 997 GT3 / GT3 RS 2007 - 2011

Diagram ref no 11

The differential outer bearing supports the rotating differential assembly within the gearbox or transaxle housing. It helps maintain correct alignment, smooth rotation, and controlled movement of the differential components as engine power is transferred through the transmission to the drive wheels.

Functions
•  Supports the differential assembly inside the gearbox / transaxle
•  Helps maintain correct differential alignment
•  Allows smooth rotation under drivetrain load
•  Supports reliable power transfer to the drive wheels
•  Helps reduce vibration, noise, and excessive internal movement
•  Replaces worn, noisy, damaged, or failed differential bearings
•  OE Match replacement for gearbox, transaxle, or differential repair.

Why Replace This Part?
Differential bearings are exposed to constant load, heat, gear oil, vibration, and high-speed rotation. Over time, the bearing can wear, pit, develop play, become noisy, or fail due to contamination, lack of lubrication, or age. A worn differential bearing may cause whining noises, rumbling, vibration, metal debris in the oil, drivetrain play, or gearbox damage if left unresolved. Replacing the bearing helps restore smooth differential operation and protects surrounding transmission components.

When to Replace This Part
•  There is whining, rumbling, or bearing noise from the gearbox / differential area
•  Excessive differential play or movement is found during inspection
•  Metal particles or bearing debris are found in the gearbox oil
•  The bearing is worn, pitted, loose, or damaged
•  The gearbox or transaxle is being rebuilt
•  The differential has been removed or serviced
•  Preventative replacement is being carried out during transmission overhaul.

Where it fits on the car
This bearing fits on the left-side outer differential bearing position within the gearbox or transaxle assembly. It forms part of the differential support system and should be installed according to the factory transmission layout and bearing preload procedure.

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

99905906400

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