Ultimate upgrade for the 9398 4x4 crawler with pendulum steering (no servo needed). I also made a pendulum steering file in the rebrickable link you can download and have a closer look
LEGO TECHNIC: 4x4 Crawler (9398) for sale online | eBay
Buy LEGO Technic 4X4 Paletli 9398 Online Türkiye | Ubuy