The Under-Slung version means the trailing arm connects underneath the axle.
The Top- Mount version has the trailing arm on top of the axle.
The HK Slider Series simply combines the HT to a slider box, resulting in a sliding tandem system.
The Top-Mount simply references that the base of the air bag is above the axle.
The Low-Ride has the base of the air bag under the axle. The Low –Ride version is common in use as a lift axle configurations.
The VANTRAAX Slider Series simply combines the INTRAAX to a slider box, resulting in a fully integrated suspension/ axle/ brake sliding tandem system.
Meritor is unique in that both the MPA and RHP use the same single shock (85919) on the center of the axle. You can tell the difference between the MPA and RHP by center upside down A-Frame support.
The MPA has an indented A-Frame.
The RHP is flat.
Notice trailing arm with cut out area. This is what they call their FUSION Beam (enhanced cast and fabricates tail section) to reduce weight. It is 26” from pivot point and center of bag. Identification difference of CBX40 and CB4000 is with axle and trailing arm.
CBX40 comes with the option of both the FUSION Beam or a Cast Beam and 5.75” diameter axle.
The CB4000 uses only the Cast Beam (which has no cut-out) and a 5” diameter axle.
Notice how the shock attach to the trailing arm just above the axle and juts up and backwards to the AirBag Top plate bracket mount.