What does the number under the red tilted truck mean?

[EviLHuAi]

[rob10]

Literally that the unit is tilted and by how much.  The 2nd number in brackets is the MAX allowed angle and if either of the 1st numbers are higher than the 2nd numbers you'll get this.  Mainly meant for SAM's etc that need to be relatively level to be able to function.

[Nealius]

Titled by how much what? Degrees? Percentage? Arbitrary unit? 

[razo+r]

1 hour ago, Nealius said:

Titled by how much what? Degrees? Percentage? Arbitrary unit? 

Doesnt really matter to be honest. Over the limit is over the limit and once within limit you don't care anymore.