Game mechanics – clutch slip effect

I have modeled a 3D bus, so I am now working on an engine and transmission script for a bus game simulator.
Everything seems fine, but I want to create a clutch slip effect and I'm really disappointed.
Here are some examples of desired result and script files.
If you have any ideas, just tell me, or if you want to give me a code for testing, you can choose a different language. I know that the Polish nation is upside down, but this is the scripting language of the game.

Example (as Ouin Ouin Ouin):

Script files:

– Engine

OSC https://pastebin.com/9a4g9r0n

Const file https://pastebin.com/6JehXXYx

Variable list https://pastebin.com/ef1jSHXy

– Transmission

OSC https://pastebin.com/Gg1xh57L

Const file https://pastebin.com/cSdAK1hD

Variable List https://pastebin.com/KqDA7qdt

If you want more examples, tell me 🙂

Regards,

Many Thanks.

Intouro Euro 5