Nice truck Hallback.
So if you are running 52K, I'm assuming that it is the ADZ.
The company I was working for when I retired had a whole fleet of KW and Western Star with the ADZ.
We ran the Stars at our division.
Logging, heavy haul off road. Trucks ran on the logging road when loaded so they were running at MAX GVW.
Keep an eye on the V-Rod bushings and bolts.
Our trucks eat them and if you didn't notice in time it would pound the crap out of the mounts. Literally days from good to bad.
The big bushing at the back will beat it self up pretty quick, keep an eye on the bolt torque.
The four 5/8" bolts on the front mounts can break (shear) right off.
Its a good system and handles the load, I just think that running on the logging roads with switch backs and such is just a bit more then they were designed for.
We ran 15 trucks at our division, tri drives. 7 days a week, 12 hour days so they miled up pretty quick.
From new we were good for about a year, now its pretty much at least one a night. Some nights more.
And with the tri axles the middle axle mount seemed to be the one that wore out first.
We found that we could push a new set of bushings into the V-rod 2 maybe 3 times and then the bore was just over-sized too much.
I kept 3 rebuilt ones on the floor at all times and 1 or 2 brand new ones in the warehouse.
Fairly easy system to work on, no tapered ends to get stuck.