Here is a sequential mod for Thrustmaster TH8A shifters that i designed. You have to place the round flat surfaces to the bed, i forgot to change the coordinate system.

You need:

2x Sequential MOD_ohne Gewinde_Federspanner.STL

(1x Sequential_MOD_ohne_Gewinde.STL) i had some issues with the support of the small pin that pushes the switch to initalize the sequential mode, so i cut it in two pieces.

or

1x Sequential MOD_ohne Gewinde_unten.STL

1x Sequential MOD_ohne Gewinde_oben.STL

and

2x Spring d=14mm, l=25mm https://www.amazon.de/gp/product/B016VQYJ9E/ref=ppx_yo_dt_b_asin_title_o01__o00_s00?ie=UTF8&psc=1

4x Ball Plunger (optional) https://www.amazon.de/gp/product/B07BNH11WZ/ref=ppx_yo_dt_b_asin_title_o04__o00_s00?ie=UTF8&psc=1

6x M3x25 screws (4x longer screws to mount it and 2x to screw in the springholder)

2x M3 nut

And some 2K Clue to clue the two pieces together

I recommend the ball plungers for that clicking sound when you shift gears...

Just clue Sequential MOD_ohne Gewinde_unten.STL and Sequential MOD_ohne Gewinde_oben.STL together, (put in the ball plungers, its a bit tricky) put in the two springs, push in the two Sequential MOD_ohne Gewinde_Federspanner.STL screw it together and have fun...

If someone wants to know, that´s the shiftingknob i use:

https://www.amazon.de/gp/product/B07B92J3MV/ref=ppx_yo_dt_b_asin_title_o01__o00_s00?ie=UTF8&psc=1