Hello,

As many have discussed on Discord, we came to the conclusion that the Mack Defense M917 has a too low collision mesh, making it drag its axles too much on the ground and obstacle making it hard to drive.
As per the model, the mesh ends just below the axles, but other trucks have their mesh end up about in the middle of the axle.
The video below shows a good summary of the situation.

Youtube Video

@nakedDave on discord made a mod which modify the collision mesh and I must say, it now performs much better and becomes much more enjoyable to drive.
May I add that the Derry Special had a similar problem when it first came out but its mesh was modified, and it now is a very fun truck to drive.

For an example, here I am, with my back axles grounded on some roots, and I cannot move any further without using the winch.

Fully support this conclusion.

I was blambing those roots that have a reputation for clinging trucks already ~ so I switched out to mods.

Lets hope this gets fixed. People have been waiting for this Mack for a long time, Saber doesn't want to ruin it with bad collision meshing that makes it near unusable.

I support this as well. It is strange how troublesome it is to traverse some terrain with this truck. While it should be a beast it falls short. I'd be quite grateful if this gets fixed, as this is really quite frustrating to see.

Consistency is key with such decisions and seeing another great truck suffering due to an inconsistency is so sad. I have a huge interest in this truck and seeing it limited by this is a displeasing experience.

my mack defence truck is fine but the game thinks i havent unlocked it