To mirror the whole truck for exporting just select everything and hit the S key, the Z key and then type -1
This will mirror the whole truck on the Z axis.
Also you may need to apply scale, rotation, and location to make the origin 0,0,0 for all meshes.
@JustaFordGuy I already knew this! Don't know why it didn't come to my mind! Thanks a lot! Shame on me! lol
I want to start showing you guys a picture of my brain after working for 5 days non-stop on my walking beam Haulmaax suspension from Hendrickson:
But... after a lot of trial and error (and I mean A LOT) I got the CDT based suspension "kind of" working, but it was behaving weird and moving sideways. Like the game did not fully respect all the constraints.
So I decided to give it a try to a regular bone based suspensio and I think this is the way to go for me right now. Of course its far from finished but its getting there. The axels, the central control arms, the side control arms and the right walking beam equalizer, are fully animated and working properly. Inly left to animate the left equalizer and the springs. Check it out here:
Don-t mind the air tanks going out of place. It's caused because they are parented to the wrong cdt. Will be corrected soon as well as many other issues that I know how to handle.
There are a number of other problems I have encountered that I haven't been able to figure out but I'll address them one at a time so I won't use this post for this. This one is only to show you guys the progress of the rear suspension so far.
Thank a lot for being supportive. Back to work 
Guys, I have an issue>
The truck behaves weird. Seems like its going to fly when it goes into a hard bump. Also noticed that it gets flipped very easy and once it-s flipped, it start trying to sint into the ground slowly and takes damage. WTF! Initially I thought that it was due to the weight but I have reduced it and still have the same issue. Finally I just copied/pasted the code from the Bison but still no luck.
My XML looks like this>
(...)
<Wheel>
<RearWheel
ConnectedToHandbrake="true"
HardpointOffsetY="-0.3"
SuspensionMin="-0.2"
SuspensionStrength="0.03"
SuspensionDamping="0.2"
Torque="default"
Type="freightliner_fl120_rear"
/>
<FrontWheel
HardpointOffsetY="-0.2"
SteeringAngle="40"
SteeringCastor="8"
SuspensionMin="-0.2"
SuspensionStrength="0.06"
SuspensionDamping="0.2"
Torque="none"
Type="freightliner_fl120_front"
ParentFrame="chassis_cdt"
(...)
<PhysicsModel Mesh="trucks/workstar">
<Body ImpactType="Truck" Mass="3500" ModelFrame="chassis_cdt" CenterOfMassOffset="(-1; 0.957039; 0)" >
<Body
CenterOfMassOffset="(1.97912; 1.08451; 0)"
ImpactType="Truck"
Mass="2000"
ModelFrame="cabina_cdt"
>
<Constraint
AxisLocal="(1;0;0)"
MinLimit="-12"
MaxLimit="12"
PivotOffset="(0; 0; 0)"
Type="Hinge"
>
<Motor Damping="24000" Spring="240000" Type="Spring" />
</Constraint>
</Body>
A little help please?
@deathcoreboy1
Shot in the dark, increase the weight and raise the COM offset. Sinking into the terrain would indicate, to me anyway, an issue with the cdt dimensions. If you can drop a screenshot it might help.
Your center of mass is really high, i used on the spintires vehicle something around -0.3 on the y axis
So far it felt realistic, I don't know if Zane changed them but for your truck they'll fit right in
Remember the center of mass isn't the center of mass of your model in blender, if more a overall balance code, see I normally use on 4x4 vehicles -0.4 to 0.6 on the Y axis depending on the lift, I like to keep it 30cm under the ground (-0.20)
The sinking into the ground can be related to it
P.d remove the pivot offset if isn't needed
@Forces Ohhhhhhh shit!!!!!!!! and there I was like a dumb calculating the actual center of the model! Thanks a ton man! I'll give it a try today!
@Mexican_420 Thank you Mex!!!
@deathcoreboy1 @Forces
Hah, I'm a dumb@$$... lol
Didn't even notice that the values for your COM offsets were POSITIVE numbers... 
@Mexican_420 Let's see if it works today when I get home. I'll report back
Well, put the center of mass to -0.3 and it works waaaay better.
Now, I want to make the frame "twist". Is there any guide or documentation about how to do this?
@deathcoreboy1
Would it be as simple as weighting the vertices of your frame mesh gradually (vertices closer to front of frame weighted more to front axle bone, vertices closer to rear of frame weighted more to rear axle bone)? Never made a truck big enough that the chassis would flex, so just a semi-educated guess on my part... 
@Mexican_420 Mex! Help!! I have a major issue! When I click on "Reload" this happens>
Also, when I install addons, they dont appear in the truck, instead they spawn deep in the ground right at the center of the map taking damage. Ohh, and the position cursor in the map does not moves regardless of my position in the game. Only happens to my truck. I think this is why the shaft is not showing up.
Edit> Also just discovered that the steam, smoke and airdust is flowing from the crater and does not move even when I move the truck
Edit2> The driveshafts shows up when I'm close to the crater.
I'm beggining to thing there is something paranormal with this crater. Maybe a UFO crash site 
@deathcoreboy1
Initial thoughts would say that the visual model of your truck isn't lining up with the collision box(es)/cdt. Has this just become a problem since you changed your COM offsets? Not sure if it's a thing with Blender, but is your truck centered at (0,0,Z) (X and Y at zero, Z will vary depending on ride height of the truck)?
Also, did you remove the PivotOffset line, as @Forces suggested?
@Mexican_420 Nevermind, I figured it out!!!! Turned out that in fact, as you said, had to do with Blender. I was selecting the main empty before exporting. In the editor, everything was parented to this empty but I never made any reference to it in the xml, so I figured out that it might be unnecesary. Went back to Blender and experted again but this time selecting the main "chassis_cdt" and boom! Works like a charm.
Actually it is behaving waaayyyy better than befor just for exporting without this empty. Driveshaft are now in possition and even smoke is comming out from the exhaust.
Here is a little teaser:
Youtube Video
Now I can focus on finishing animating the springs and the front suspension.
Thanks again @Mexican_420
Hey guys, would anybody tell me what's this code for?
<OcclusionVolume
HalfSizeZ="1.706"
HeightFront="1.36"
HeightRear="0.703"
MinX="-3.649"
MaxX="4.006"
>
<FullOcclusion HeightFront="1.294" HeightRear="1.185" />
</OcclusionVolume>
Since I don't know what it does, I have no idea of which values to enter.
@deathcoreboy1
https://steamcommunity.com/sharedfiles/filedetails/?id=1583079240
It's a map guide, but the Occlusion section (Model Shadows) should have all you need. 
@Mexican_420 Oh wow!! that'a a comperhensive guide! Thanks as usual Mex!!
@deathcoreboy1
Yeah, there's tons of stuff in there that can also be applied to modding. Explains a bunch of constraints and which values to adjust for certain factors, helped me get a much better handle on how to animate stuff on my trucks (figuring out how to set some things up in 3DSMax so the constraints affected them properly was a bit rough at first).
