BMW E60 M5 33102284030 Refurbished Limited Slip Differential ZF 45%

For the BMW E60 M5 (and E63/E64 M6), the part number 33102284030 refers to the core final drive assembly. A “Refurbished ZF 45%” unit is a popular aftermarket upgrade that replaces the often-problematic factory M Variable Viscous unit with a traditional clutch-type ZF Limited Slip Differential (LSD) set to a fixed 45% lock.

1. The Factory vs. Refurbished Upgrade

The original E60 M5 differential (GKN Viscous) is known for the “M-Clunk” and a slight delay in locking while waiting for fluid pressure to build.

2. Technical Specifications (33102284030)

• Final Drive Ratio: 3.62:1 (The standard ratio for S85 V10 SMG models).

   

• Internal Setup: Typically rebuilt with 4 to 6 high-performance clutch discs and 45-degree ramp angles to achieve the 45% lockup.

• Ramp Angles: Usually set to a symmetric 45°/45° (2-way) or 30°/45° (1.5-way) for a balance between aggressive acceleration and stable deceleration.

• Bearings: Refurbished units generally include all new Timken or Koyo tapered roller bearings and fresh OEM seals.

   

3. Why 45% Lock?

The “45% ZF” setup is considered the “Sweet Spot” for the E60 M5:

• Traction: It provides immediate lockup upon throttle application, allowing the V10’s 507hp to be put down more effectively out of corners without waiting for one wheel to spin.

• Stability: A 45% lock offers significant engine braking stability, helping to keep the heavy E60 chassis composed during high-speed downshifts.

• Drift Control: Unlike the viscous unit, the ZF clutch-type is highly linear, making the car much easier to control in a sustained slide.

4. Refurbishment & “M-Clunk” Fix

The “Refurbished” label is critical here. A professional rebuild under this part number specifically addresses:

1. Backlash Adjustment: Setting the ring and pinion play to tight factory tolerances (usually $0.08mm – 0.12mm$) to eliminate clunking.

2. Side Flange Play: Replacing the internal side gear shims to prevent the “sloppy” output flange feeling common in used units.

3. Case Refinishing: The iron housing is usually sandblasted and coated in high-temp black paint to prevent the common surface corrosion seen on E60 underside components.

Installation & Break-in

• Oil: Must use a high-quality 75W-140 GL-5 gear oil with limited-slip additives (e.g., Castrol Syntrax Limited Slip or Motul Gear Competition).

• Break-in: New clutches require a “Figure-8” break-in procedure (approx. 20 minutes of tight slow-speed turns) to bed in the friction plates and prevent “chatter.”Note on Manual Transmission M5s: If your M5 is a rare 6-speed manual, the factory ratio is 2.93:1. Installing this 3.62 unit will significantly increase your acceleration but will also increase your cruising RPM and throw off your speedometer calibration.