Automatic transmission 6HP-21 3.0i N53 BMW E90 E91 E92 E93 E60 55TKM

high-value unit, specifically the ZF 6HP21, which was the “Technical Update” (TU) version of the 6HP19. Given the 55,000 km (55TKM) mileage, this is an excellent replacement candidate for the N53-powered 3-series and 5-series LCI (Life Cycle Impulse) models.

Technical Specifications & Fitment

The 6HP21 is a 6-speed automatic designed to handle the direct-injection power delivery of the N53 naturally aspirated straight-six engine.

• Manufacturer: ZF Friedrichshafen

• Transmission Code: 6HP21 (1071 Series)

• Engine Pairing: Primarily the N53B30 (3.0L Inline-6).

• Chassis Compatibility:

  • 3 Series (E90/E91/E92/E93): 325i, 330i (LCI models).

  • 5 Series (E60/E61): 525i, 530i (LCI models with the electronic “Joystick” shifter).

  • X3 (E83): Late-model 3.0i variants.

Key Points for Inventory & Listing

If you are adding this to your digital storefront or preparing it for a high-end client, these details add significant value:

• Mechatronics Integrity: At 55TKM, the solenoids and internal seals are typically in peak condition. For long-term reliability, it is often recommended to replace the “Mechatronics Seal Kit” (the four rubber sleeves and the bridge seal) during installation as a preventative measure against future pressure loss.

• Fluid Condition: Mentioning the fluid is “clear and free of burnt odor” is a major selling point for low-mileage ZF units. This gearbox uses ZF Lifeguard 6 (Gold) fluid.

• The “Joystick” Interface: For E60/E61 models, ensure the buyer knows this is compatible with the electronic shifter (GWS) common in LCI vehicles.