An idea about the gear indicator. Concern about there barely have no space in the back of the bugatti. I decided to place the indicator in front of the car. The basic idea is to let the movement for the yellow gear directly transfer to the Passenger seat.
All the new parts and replacement parts are show in red and the other color mean the original parts.
As we can see from the first picture, an axle transfer the movement to the right side of the car. It will turn 90 degrees by using a pair of gears.
After movement turning 90 degrees, on the same axle, there is a belt gear, it could be replaced by PART 2983, I can't find if in the database. Then, the movement will transfer vertically to another belt gear, where I placed a 1/2 bush (actually, a bush can also be used as a belt gear). It also need to replaced by PART 2983.
On the same axle, there is a 12 Tooth Bevel. It will transfer the movement 90 degrees again.
Finally, on the last axle, it pass through a hole on the panel and present any action from the Gear lever.
There remain 3 issues that could be further optimized.
The first, which I worried about most is the pair of belt gears, I hope they could work well, but I don't have that part to test.
Secondly, the ratio between gear need to be as close to 1:2 as possible. Again, I don't have data of belt gears, With now exist design, When push 8 times of the gear lever, the indicator will Rotating less than 360 degrees.
Thirdly, the mount of axle hold base at left side of the third picture, is not concise enough. I am sure there have better solution.