I know you did that helicopter tutorial, and the same principles apply, but you do have to do a bit of digging to get wheeled vehicles set up properly.
But once you know how to do it, it's extremely simple.
I probably should do a tutorial myself, but been flat out on other things (check my moddb profile pictures for a "small" glimpse kaku

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I'm not going to write a full blown tutorial right now since you know most of what you need to do already since you followed that helicopter tutorial before.
So for this case, I'm going to assume that you've made a very VERY basic vehicle.
This vehicle has a chassis that is pretty much a box. It also has 4 wheels.
The chassis can be named whatever you like, it really doesn't matter, you could call it "bob" if you really wanted to.
But since it's usually good to stick with proper naming conventions, you should called the body of the vehicle "Hull".
Clone the hull as a copy, and name this copy "Hull_proxy".
Now before I go on, you could actually name the wheels whatever you like if you edited the script file to use those names, however for the purpose of this little tutorial, you will use the naming convention used on a vehicle script file already used in Crysis.
So go into the Cryengine, drag and drop the Civ_Car into the level and open the vehicle up in the vehicle editor).
Go to "Save As.." and name the save file to whatever your vehicle will be called.
Restart the cryengine, drag and drop your new vehicle down into the editor, then open it up in the vehicle editor again.
Click on the little check box that says "Wheels".
A bunch of little wheel icons will appear in the structure list, each named "wheel01" through to "wheel04". (Don't shut down the editor or vehicle window just yet though).
So now you know what to name your wheels. (NOTE: For the LTV, I believe it's just "wheel1" through to "wheel4")
Now go back to 3ds max and name your wheels just like below:
wheel01 is your front left wheel
wheel02 is your front right wheel
wheel03 is your rear left wheel
wheel04 is your rear right wheel
(NOTE: Also make sure that your wheels pivot points are centered, so that you don't get wierd wobbly wheels....unless that's what you want)
Now go and set up your multi-material the way you want it to be set up.
Your wheels material doesn't need a special set up, it's just the same as any other material, using the cryshader with default physicalize settings.
Now create a dummy and call it "hull" or...body, or whatever you want...once again this doesn't matter.
Now you will want to make a drivers seat, so hopping back over to your vehicle in the cryengine, click on "driver" in the structure list.
You will notice where it says "enterHelper" the value is "passenger01_enter_pos", and where it says "sitHelper" the value is "passenger01_seat_pos".
As far as I can tell, the enterHelper is only for the AI, so that they have to move to the location of the enterHelper in order to get in the vehicle, otherwise if you don't have that helper, they will just walk directly to the vehicle and hop in wherever, which may look a bit odd.
So back in 3ds max, create a dummy called "passenger01_seat_pos" and place this where you want the drive to be seated. (NOTE: This will take some testing in order to find the right spot).
If you want to create the passenger01_enter_pos, you can do that too, but it is not necessary for this example.
Now, I haven't needed to set up things like the steering wheel, or lights, or particles, but I can guess that by ticking the Vehicle Helpers tickbox you should be able to find things like the exhaust point, engine smoke, light positions etc.
For the steering wheel, I can only assume that on your 3ds max model you need to make a steeringwheel called...."steeringWheel" with a pivot point that has been centered just like your wheels.
The only thing that might be different though is that unlike the wheels, the steeringwheel is of the class "AnimatedJoint" which makes me think that you might actually have to set up a joint for it...I don't know how to rig in 3ds max so i'll just skip over that bit.
I guess that now you've got a hull, a hull_proxy, 4 wheels, a dummy named hull, and a dummy for your drivers seat, you can select all of your mesh (not the dummies) and reset the XForms on them, then convert them to editable polys.
After that, link the hull mesh and hull_proxy mesh up to the hull dummy, and also link the sit position dummy up to the hull dummy.
Link the wheels to the hull mesh.
After linking it all up, save your max file to the location where your materials etc will be going.
Export the materials.
Then export the actual object as you did it with the helicopter.
Now you need to jump back over to the cryengine, go to the vehicle editor that should still have your vehicle file open, click on the part that says "body" right at the top.
In the properties, open up the "animated" section, go to the filename parameter and open up your cga file that you just exported out of 3ds max.
If you have a destroyed verson of the vehicle, change the filenameDestroyed file aswell.
If you don't have a destroyed verson, just use the same one as in filename.
Then save your vehicle file to update it.
Your new vehicle should appear instead of the old civ car model.
Now you should be able be able to jump in your new vehicle and drive it around.
If you find that it tips over and has problems like that. Open up the vehicle editor with your vehicle again, click on "massBox" in the Structure, then resize and move the massbox to where you want the mass of your vehicle to be.
(NOTE: If you have a vehicle which is skinny at the front, and chunk at the back, and your mass is at the back, your vehicle will probably just flip over backwards. So try to move the mass forward and cover the whole vehicle's base unless you want the vehicle to do a backflip

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And that should be all there is to it.
Once again, I really should write a proper tutorial with pictures, instead of just blabbing about it like a broken record, but hopefully this blabber will get you through the basics at least.