FAQ N54 N55 S55 to 6HP28 BMW Adapter - BMW E9x E8x E6x
- Guru Autowerks
- Jan 2
- 6 min read
Updated: 6 days ago
GA1 N54 N55 S55 to 6HP28 Diesel Transmission Adapter Kit
BMW E90 E91 E92 E93 E82 E88 E60 E61
What is the Total Conversion Cost for RWD & AWD 6HP28
Conversion cost ranges from ~$3500 to $4000 for RWD and $3700 to $4500 for AWD.
This estimate range includes all components needed utilizing a stock 6HP28; Labor cost not included.
Final Cost will vary based on choice of TCU, Tuning, Coding and optional transmission upgrades.
From mild to wild this setup has ample options to chose from & plenty of room to grow!
What other components & services are required to complete the conversion?
6HP28 Transmission w/Torque Converter – From 03/2007+ BMW M57N2 Diesel Models
3 Gallons ATF – Adrenaline Speed Shift ATF or Similar Group IV Synthetic Fluid Recommended
Misc Parts – New Valve Body Bridge/Sleeve Seals, Mechatronic Tube Seal, Filter, Input Seal etc.
Coding – Houston BMW Coding or BimmerGeeks ProTool App.
Tuning – OEM BMW TCU: Sutphin Tuning & xHP Flashtool or Standalone: Quick6/HTG etc.
Labor – We Povide direct project support from A to Z for DIY or Professional installations.
How much power can this transmission setup support?
Stock 6HP28 is Manufacture Rated @516 lb-ft or 700nm but commonly handle 600-800lb-ft with ease.
6HP28s can be built to handle 1000-1500+ lb-ft TQ with upgraded clutch packs & billet components.
Proven 7 & 8 Second 1/4-Mile Drag Racing Capability with 6R80 Components from 5.0 Coyote Mustang Platform. Start small and have plenty of room to grow or go BIG and send it on ALL THE BOOST!
What Transmission is compatible?
BMW ZF6HP28 (aka "6HP26Z") 6-Speed Automatic Transmission.
RWD USA – 2009 to 2011 BMW 335D
AWD USA – 2009 to 2013 BMW X5D
Europe & other Countries several options available; 330, 335, 530, 535, X6D, X5D, X3D.
Please consult with use directly before purchasing ANY transmission so we can ensure compatibility.
How much does the transmission cost?
RWD USA ~$400 to $800+
AWD USA ~$600 to $1000+
Europe & Other Countries – Varies Widely
Where do I find and purchase the transmission?
We provide direct support to all customers and encourage them to work with through this process.
Car-Part, eBay and LKQ are most common recommended sources for used transmissions.
Be mindful when purchasing from individuals or any business with cash/no receipt. Ask what the return policy is ahead of time to avoid surprises. Request our guidance before final purchase!
What help do you provide sourcing these transmissions?
Using the donor vehicles VIN number we research Vehicle & Auction/Sale History to verify the advertised mileage and condition of the transmission is accurate. We also check reviews of the Auto Parts Yard selling the product and when necessary call or email to ask various questions before approving it for purchase.
This process gives the customer a handful of vetted transmission options to choose from. While we cannot guarantee the condition of these used transmissions the support provided greatly reduces the risk associated with purchasing used components; especially if unfamiliar with the process.
When should I purchase my transmission?
While you can purchase parts at anytime we recommend waiting until approximately 1-3 weeks ahead of the installation date. Most Used Parts have a 30 day money back return period with a receipt. Within the first 30 days a pre-installation inspection is recommended so if any issues are discovered you can quickly return it. Keep in mind the buyer is usually responsible for returning the item locally or paying for return shipping cost which can be substantial.
Are any custom modifications required to fit the 6HP28 Transmission assembly?
Two small modifications are required for reusing the BMW N54 N55 S55 Starter.
Mod # 1– Drilling out the threaded hole in starter with a 7/16" drill bit to convert to a through hole. Necessary Tools for Mod # 1 = Hand Drill & 7/16" Drill Bit – Optional: Spray Lubricant, Bench Vice.
Mod 2 – Clearance 6HP28 Bell Housing for BMW starter fitment; Shaving 1 Small location inside bellhousing. Necessary Tools for Mod # 2 = Die or Angle Grinder with Flap Disc/Carbide Burr/Grinding Stone etc.
How many and what gear ratios does the 6HP28 have?
6HP28 is a 6-Speed Automatic and has identical gear ratios as the BMW ZF 6HP21 transmission. Six forward speeds, with gear ratios of 4.17, 2.34, 1.52, 1.14, 0.87, and 0.69:1.
What driveshafts are compatible? OEM, M3, Ford 8.8?
OEM 2-Piece Driveshafts for E9x & E8x – 100% Compatible – No Modification Necessary OEM 2-Piece Driveshafts for E6x – 100% Compatible – Minor Modification Required
M3 Driveshaft & Differential – May or May not require modification depending on Driveshaft used.
Ford 8.8 1350 U-Joint driveshafts are directly compatible with the Dodge Ram 8HP70/75 "Truck" Output Flange; Requires using matching OEM Dodge 1350 U-Joint Flange Part# 68417915A – Please consult with us for further assistance.
What is a TCU?
"Transmission Control Unit" is the computer which controls the transmission much like an ECU/Engine Control Unit.
What TCU can I use to control the transmission?
03/2007+ Gen2 6HP28/6HP26 TCU – Used with ZF 063 M-Shift Valve Body or 065 E-Shift Valve Body
Standalone TCU Options – US Shift Quick 6
What is required to use Standalone TCU?
Most standalone controllers installation will require some basic/intermediate level wiring & computer skills. Installing a basic wire harness that requires routing/trimming, terminate the ends and/or tapping into existing vehicle wires. Using computer to update/flash firmware/configurations, various amounts of remote or in person coding/tuning/tweaking. The complexity of standalone installation greatly depends on the controller chosen, its capabilities & components supplied with it. US Shift Quick 6 is compatible once building the 6HP28 transmission with 6R80 internals, valve body etc. Please consult with us directly about the options available & their complexity/required work.
Is any wiring required?
No – BMW TCU & ZF 063 Valve Body no wiring; Simple Coding Procedure and Custom XHP Tune.
Yes – Standalone TCU wiring requirements will vary depending on the features and controller chosen.
What shifter do I use?
OE BMW TCU w/M-Shift 063 Valve Body – E-Series 6HP Mechanical Shifter – No Wiring Required
OE BMW TCU w/E-Shift 065 Valve Body – E-Series 6HP Electronic Shifter – Plug & Play Harness
US Shift Quick 6 M-Shift 6R80 Valve Body – E-Series 6HP Mechanical Shifter or Lokar 6R80 Shifter
Will cruise controls work?
OEM BMW TCU – Yes; No additional wiring.
Standalone TCU – Yes with wiring/coding; Dependent on chosen control unit and capabilities.
Will steering wheel paddle shifters work?
OEM BMW TCU – Yes; No wiring if vehicle is equipped with paddle shifters. Can retrofit if not equipped.
Standalone TCU – Yes with wiring/coding; Dependent on chosen control unit and capabilities.
What Torque Converters are compatible?
OEM 6HP28 Diesel TC – Stock ~3000 RPM Stall Speed – 335D, X5D and other similar M57N2 6HP28.
OEM 6HP21 Gas TC – Stock ~2500 RPM Stall Speed – 335i, 135i, 535i and similar N54/N55 6HP21.
High Stall OEM 6HP21 TC – Choice between 3000-3400 RPM Stall Speed – Send a core for modification.
*6HP28/6R80 Hybrid Torque Converter Options*– REQUIRES 6HP28 to be converted to 6R80 internals.
Circle D 245mm & 252mm Pro-Series 6R80 Torque Converters – Custom order & spec'd to your build.
32 Spline Input & 27 Spline Stator – Custom made to work with your OEM N54/N55 Flex Plate.
Does my stock exhaust fit?
One small modification is Dependent on Downpipe & O2 Sensor location – Additional clearance for O2 sensor.
Optional Mod # 1 – Cut/Grind misc. fins/ribs on RH side of 6HP28 Transmission for downpipe 02 Sensor Fitment.
Necessary Tools for Optional Mod # 1 = Die or Angle Grinder with Cut or Flap Disc/Carbide Burr/Grinding Stone etc.
What about the transmission cooler setup?
Our Kit includes components to adapt an existing AN8 or AN10 transmission cooler.
8HP AN Adapter, 8AN PTFE Line Kit w/10 fittings, 10AN/8AN Reducers & A/T Radiator Block-Off for deleting OEM Cooler.
OE Cooler is not Recommended/Compatible. Add AN Cooler Core & Thermostat to complete your cooler setup. Not sure what parts you need? Consult with us directly to add a cooler core & inline thermostat to your kit.
Is this compatible if my E-Series N54 N55 S55 car is Manual, DCT?
Yes but vehicles with Manual or DCT Transmission will require additional parts, coding, wiring and labor.
Consult with us before purchasing to ensure smooth process.
What about BMW E-Series N51 N52 & N53 compatibility?
Yes; Available by Request.
How does shipping work?
Our preferred method of shipping is UPS Ground; Fully Insured & Signature Required.
Upon final payment customer is notified of estimated shipping date.
Confirmation of package drop-off and tracking information are provided ASAP.
Expedited & International shipping quotes available upon request.
What about local sales tax?
8.25% Sales Tax will be applied to Texas orders.
What about International import fees?
International customers are responsible for all customs import taxes, duties & tariffs.
