Part nr: 33120026232
Next to the original BMW driving dog, an after-market version is available in the market.
At first view, the after-market product gives the impression of high quality machining.
However, there are at least 2 flaws:
1. the geometry of the splines:the splines of the after-market part almost have a V shape instead of the trapezium shape on the original part. This V-shape is normally seen on worn splines
2. The diameter of the needle bearing seat measures 39.94 mm whereas the original parts measures 39.97 mm. This will result in too much play on the needle bearing
The impression is that this is a case of reverse engineering, whereby the measurements were take on a worn driving dog.
Testing the Rockwell hardness of the bearing surfaces would be interesting, but considering the above mentioned flaws, even a positive result would not qualify this after-market part.
