Just replace tractor.dff inside gta3.img archive or use modloader.

handling.cfg
TRACTOR 2000.0 5000.0 3.0 0.0 0.0 -0.2 70 0.90 0.85 0.5 4 70.0 20.0 90.0 R D 15.0 0.20 0 50.0 2.0 0.12 0.0 0.25 -0.05 0.5 0.0 0.26 0.50 9000 200311 1340405 1 1 28

carmods.dat
tractor, nto_b_s, nto_b_tw

Check this mod here:
https://www.youtube.com/watch?v=urr8EcuQjvI

And subscribe to my YouTube channel for more great mods:
https://www.youtube.com/channel/UCHWvKWerWjylBHbgKjGy71g

Here you can download more mods:
https://www.gtainside.com/user/Dragomazing