Main shaft bearing. Porsche 993 / 997 Turbo / GT2 / GT2 RS / GT3 / GT3 RS › 99911018103

This OE Match main shaft bearing supports the gearbox shaft as it rotates, helping maintain its alignment within the transmission housing. 

Fits

• Porsche 993 Carrera / RS / Turbo 1995>>
• Porsche 997 Turbo 2007-09 G97.50
• Porsche 997 Turbo GT2 2008-09 G97.88
• Porsche 997 GT2 RS 2011 G97.88
• Porsche 997 GT3 / GT3 RS 2007-11 G97.90/92
  
  Check the production date and original reference before selecting the bearing.
  
   Diagram ref no 7
  
  What Is This Part?

This is a cylindrical-roller bearing used within the gearbox housing and transmission-cover assembly. Its rolling elements allow the shaft to rotate while the bearing supports it relative to the housing. Correct shaft support forms part of the gearbox's internal alignment, alongside the other bearings, retaining components and housing seats. Replacement is an internal transmission repair rather than an external adjustment.

What Does This Part Do?

• Supports the shaft: Provides a bearing support within the gearbox housing.
• Allows rotation: Uses rolling contact between the bearing surfaces as the shaft turns.
• Maintains alignment: Works with the remaining shaft supports to keep the rotating assembly correctly positioned.
  
  Why Replace This Part?

Replace the bearing if inspection confirms damaged rolling surfaces, excessive wear or rough rotation. Inadequate lubrication and contaminated oil can damage bearing surfaces, so the cause of deterioration should be investigated alongside the bearing itself.
Particles circulating in the lubricant can indent the rolling surfaces and contribute to further deterioration. During repair, inspect the shaft seat, housing seat and associated retaining components rather than assuming that replacing the bearing alone will resolve the underlying problem. 

When to Replace This Part?

• Confirmed surface damage: Pitting, flaking, scoring or corrosion found during dismantling warrants assessment and replacement where necessary. 
• Rough rotation or abnormal play: Inspect the bearing and its mounting seats against the gearbox repair specifications.
• Gearbox whine or rumbling: Investigate the complete transmission before identifying this bearing as the cause.
• Metallic debris in the oil: Establish which internal components are deteriorating before reassembly.
• Removal or fitting damage: Scratched rolling surfaces or impact damage can make a bearing unsuitable for reuse. 
  
  Where Is This Part Fitted?

Location: Inside the gearbox, within the gear-housing and transmission-cover assembly, supporting the main shaft. Access requires transmission dismantling appropriate to the gearbox type.

Technical Details

• Construction: Cylindrical-roller bearing.
• Dimensions: 30 × 62 × 16 mm, as identified for the gearbox applications.
• Production-date distinction: The Porsche 997.2 GT2 RS application has a reference change on 01.07.2011.
  
  FAQs

• Does gearbox noise prove this bearing has failed? No. Other bearings, gears, lubrication issues and surrounding drivetrain components can produce similar symptoms. Diagnosis should establish the source before parts are ordered.
• Should other parts be checked during replacement? Yes. Inspect the shaft and housing seats, retaining components, other bearings and seals, and check the lubricant for contamination.
• Can one bearing be replaced during a rebuild? Where inspection supports it, an individual bearing may be replaced. Assess the remaining bearings rather than assuming that all are serviceable or that all require renewal.
  
  Product Summary

• Product: Main shaft cylindrical-roller bearing.
• Brand: OE Match.

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

99911018103

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