Tufftruckparts.com - Suspension Strut Assembly
Struts are very similar to shocks internally with oil and valves, but they are constructed differently on the exterior. You see these custom truck parts like struts are designed to be an integral part of the suspension. Unlike shocks, if the struts weren't attached, the car would fall flat on the ground, and be totally immobile. The wheels would flop around, because they would only be attached to the lower control arm, which just isn't enough. On a typical strut, above the coil-spring is what is known as the upper strut mount, and under that is usually a bump-stop which is covered by a rubber boot. These pieces can all be replaced individually, or replaced together as one unit called a "loaded strut". Replacing a loaded strut on a vehicle is dramatically easier than replacing any one of the individual parts, because you don't need to compress the coil springs, or align the strut mounts properly. It is all done for you. Some custom truck parts struts have replaceable "cartridges". A cartridge is basically the "shock" section that sits inside the body of the strut. Not many vehicles were built with this custom truck parts style suspension, but they are out there. The beauty of them is that the strut cartridge is often removable from under the hood, which means the strut itself doesn't need to be taken out of the car at all. That's less labor for you, and no alignment needed.