I need a coder for an arduino based CAN project.

I have no business, this is just a personal venture. It's automotive based. I have a car that originally came with an automatic transmission that I have swapped in a manual transmission. The engine/chassis combination never came with a manual transmission so the TCM is now missing and the car is new enough (2003) that the ECM is not happy. I'm looking to use an arduino to spoof the TCM. I'm not looking for complete mimicry just a few specific CAN messages sent when things happen. Most prominently a gear indicator. (eg; if the vehicle speed is 10-19mph, then a CAN message is sent out saying the car is in 1st gear. If 20-29mph then a CAN message for 2nd gear, etc).