Febi 31500 Axle Differential Seal

Febi 31500 Axle Differential Seal

Febi 31500 is an axle differential seal built for rear differential sealing service on select Audi applications. It uses ACM material and measures 45.0 mm inside diameter, 60.0 mm outside diameter, and 15.0 mm thickness for the specified fitments.

For Audi A4 Quattro, A5 Quattro, A6 Quattro, A7 Quattro, A8 Quattro, S4, S5, S6, S7, S8, RS4, RS5, RS6, Q5, SQ5, A4 allroad, allroad, and A4/A6 chassis applications, this seal supports rear right and rear inner differential sealing positions where listed. Febi 31500 is also referenced for vehicles without Active Differential in several rear right applications.

Key Features

• ACM sealing material for differential service
• 45.0 mm inside diameter for the listed axle and differential applications
• 60.0 mm outside diameter and 15.0 mm thickness
• Fits rear right and rear inner positions where specified
• Cross-reference part numbers: 0AR 409 399, 0AR 409 399 B

Detailed Description

Febi 31500 is an axle differential seal for Audi driveline and axle repair work. The seal dimensions and ACM construction are matched to the listed rear differential locations, including rear right fitments on many quattro models and rear inner fitments on earlier A4, A5, A6, A8, S4, S6, S8, RS4, and RS5 applications. If you are servicing an Audi A6 Quattro rear right differential seal, an Audi A4 Quattro rear inner seal, or a similar quattro rear axle location, this part number is listed for those applications.

Febi 31500 is identified for model years spanning 2002 through 2018 across the included Audi fitments. The part number 31500 is the key reference for ordering and service matching, and it is also associated with OE-style cross references 0AR 409 399 and 0AR 409 399 B for the same application.

What It Helps Fix

• Differential fluid seepage at the rear axle seal area
• Oil residue around the rear right or rear inner differential housing
• Seal wear from age, heat, and driveline mileage
• Leak-related maintenance on Audi quattro rear differential assemblies
• Noise or contamination concerns caused by low differential fluid levels

Installation Notes and Tips

Confirm the vehicle’s exact year, model, and differential position before ordering. This listing includes rear right and rear inner applications, and some fitments note use only on vehicles without Active Differential. Match the seal dimensions and transmission or axle notes shown for the specific Audi application before installation.

Inspect the sealing surface, housing condition, and differential fluid level during service. Replace worn or damaged components in the area as needed to complete the repair correctly.

Quality Assurance

Febi is a recognized aftermarket brand for European vehicle service parts, and this seal is cataloged with the specified dimensions and application data for accurate fitment selection. Febi 31500 is listed for Audi driveline repair use across the stated model years and positions.