BMW E90 xDrive Transfer Case Mount Insert

I originally started selling these in 2022, but decided to release the files for free. PowerFlex blatantly copied my design in 2024, so now there is very low demand. So, as a gesture to PowerFlex (perhaps a gesture involving a certain finger) I am making this open source, so you can make your own. I also have designs for certain X3 and X5 models - contact me for more info on those. Native SolidWorks files are also here. Please do not use this for commercial purposes, this would be incredibly unethical.

The objective of this part is to stiffen the transfer case mount, which allows a lot of deflection during hard cornering and RPM changes (torsional flex). This can really get in the way of clean shifts during “aggressive” driving. You don't need to remove or replace the mount itself to install this part, and it is completely reversible if you don't like it.

Several files are attached:

• One is the main insert
• One is the installation tool
• There are 3 sizes for the installation shims.  I normally would print all 3.

Suggest to read the installation instructions PDF first, which is also attached here. It helps you get an idea of how this goes together, and may help you with planning the print job.

Video for more context: 

For the main insert, here are my TPU hardness recommendations based on a few years of customer feedback:

• 75A Shore hardness TPU for a street driven car. The best material I found is SpiderFlex TPE, which you can find easily from several vendors. It prints very reliably with my direct-drive toolhead at low speeds (maybe 25-30 mm/s). 
  • For a softer (effective) hardness, maybe print with 40% gyroid infill and 8 walls. Of course you can experiment with different settings as you see fit.
• If you are more interested in a DE / autocross / track day application, 95A Shore hardness is a reasonable option. NVH levels will be increased as you go stiffer, so expect some gear whine at certain RPMs and a rougher idle. A lot of people have noted that they increased their idle by ~200 RPM to help with this.
• For the most extreme race guys, I've even made a few with 64D Shore hardness material and beyond. NinjaTek 'Armadillo' is almost as rigid as ABS when printed! BASF also sells some stiff TPU which can be found between 60-75 Shore D. This will result in a part almost as stiff as a construction hard hat or a bowling ball. 

The installation tool, this is more or less a typical 3D print. I normally use PETG or ASA because that's what I have laying around. But PLA would work fine. Just use at least 4 or 5 walls, and I suggest 5 or 6 top / bottom layers. When you see how the tool applies pressure to the mount, you'll see what I mean. Suggest at least 30-40% gyroid, cubic, or 3D honeycomb infill, etc. It takes a high compressive load.

The shims are made with TPU, to help with vibration management. I normally just use whatever 95A material is around, it's less important here for NVH. You can scale the Z dimension in your slicer to get a different height, as needed. I normally ship a combination of big and small shims so that there is some combination which is just about right.

None of these files require any supports, FYI.

With all of that being said, enjoy - and thank you for the business over the years!