The model does not have any LODs, which is what is causing the issue.
There are two possible solutions to this, one of them is lazy and sloppy, the other one is tedious (and still kind of sloppy).
Solution 1 - increase the L0 distance to the maximum from the vehicles.meta. May cause performance issues and isn't the proper way to address it anyhow, because clients will render the model for miles.
Solution 2 - Go through parts one by one. For instance, we'll take the boot. Uncompound the boot, make 2-3 copies of the L0 (uncompounded part, not the dummy). Hide the L0 and begin making LODs for the part.
I personally use the polygon mesh optimization tool (available in the submesh toolbar) at 75 percent, if you use it, click on the L1 once, the L2 twice, and the L3 three times. The tool merges polygons for you, thus lowering the amount used (on the part). Sometimes that creates holes as it tries to merge two polygons that aren't proportionate to each other, but IMO it doesn't matter, given that people can't see it from distance anyways.
After done with all of that, just compound the part again. Boot dummy as default, the initial part itself as L0, and the rest as L1, L2, L3.
There is a thorough guide for LODs under the guides section here, which explains things more thoroughly. It also includes a section about polygon welding, which might allow you to control the quality of the LODs and merge polygons properly, but I personally use Solution 2. While sloppy, it's fast, and it works (reasonably).
Guide
LOD Models
This guide is explaining the purpose of LOD models and provides information about setting them up.
