BMW ZF5 Shift Pin Drift Punches

These punches are used to drive new shift detent pin bushings to the correct depth in the ZF5 transmission case. These are BMW special tools 232360, 234022, 234023, 234021, and 233110

These punches are based on the drawings from the excellent DIY guide at https://web.archive.org/web/20161019184449/http://webspace.ringling.edu/~dplassma/bmw_diy/shift_pins/shift_pins.html

I did resize the handles, based on the dimensions of the aftermarket punches from Thayer Motorsports. These punches are intermittently unavailable from Thayer, and entirely unavailable from BMW from what I can find. Custom machining quotes were in the realm of $150-$200 per punch, so I set out to print my own. 

However, Thayer ran another production run and I was able to get a set of metal punches before I found a material that would work for this high impact application. I still believe these can work, but I didn't get a chance to try PLA, and the PETG I was using was not stiff enough (looking back, PETG is possibly the worst material for this application…). Regardless of print settings, the material would deform due to the small working surface area of the punches.

I don't have another good opportunity to try them since my transmission has been serviced now. I'm posting them in the hopes that the models can help someone out that can't get their hands on the Thayer punches. I believe PLA might work with the right print settings, but even better would be some sort of fiber reinforced PLA, PC, or Nylon.

These should work for any ZF 5 speed manual gearbox, which were in many BMWs in the 90s and 2000s, including E36, E46, E34 and E39 models. Measurements and testing were done on the ZF S5-31 from my early 2003 330i.

The dimensions are very exact, they're extremely critical for this application. Your printer should be able to recreate better than 0.1mm dimensional accuracy, ideally closer to 0.05mm.

Update Nov 19 2024

I've added .step files in case someone wants to send these out for CNC with an online service like JLC or RapidDirect. These days it seems like Race German also makes a reproduction set of punches which would be much more economical. 

I've also added a 6th punch, based on the dimensions in a different guide for the 3rd detent pin that lives next to the 5th and Reverse pins (I couldn't find a BMW number for this punch, if anyone knows it please message me). To summarize the guide, it's mostly the same as the process for the 5th/reverse pins but there are two smaller bushings stacked one behind the other. Once the old ones are removed, one new bushing gets punched in to full depth, the other about ¼ inch. You'll need the following parts to complete the repair:

• 2x bushing 23117533394
• 1x spring 23311224819
• 1x pin 23311224823
• 1x lid 23311224825
• 1x lid clip 23317531374

Recommended print settings:

• 0.2 layer height
• 5-7 perimeters (you want the diameters at the tips to be solid)
• 5-7 top/bottom layers
• 40+% cubic (or similarly structural) infill throughout
• 100% infill for the top portions could help strength, but it's probably better to use more perimeters throughout
• No supports