Doesnt switch gear, any help?

Assuming it’s a manual transmission, have you checked the shifting linkage to make sure it’s not broken right? If you are using the clutch and it’s shifting into 1 and 2, seems that the clutch cabling is engaging fine.

This is just an example of bushings worn or the cable out of alignment: https://mercedessource.com/problems/tran...

Basic troubleshooting for you to do:

https://axleaddict.com/auto-repair/Manua...

Next time, check those first before posting as people will want photos and such. Also state the type of transmission as that’s extremely relevant to troubleshooting/diagnosing.