I believe the 4500# axle is the part time 8 lug axle. Thats whats on my 73 W200. Mine also has bigger lugs than a full time 8 lug 44.

-Jon

70 challenger convertible. 340/5 speed. blown, intercooled, efi, blah blah blah 71 valiant scamp 318/A833OD/AC/PS 00 dakota RC 4.7L 5 spd autoX'r. SRT10/T56 swap in process 73 W200 Power wagon, PTO winch, 4 spd