The Bilstein B6 4600 rear shock (24-002561) is a 46mm monotube, gas-pressure damper built for the stock-height Toyota Land Cruiser FJ60. The manufacturer says the B6 is an improved OE replacement that adds firmer, more precise damping at factory ride height, so you keep your original springs and do not need to lower the truck. Its monotube design uses a working piston the manufacturer describes as about 63% larger than a twin-tube's, for more consistent control on rough trail and highway. Each unit also goes through endurance, salt-spray, and scratch testing before shipment, which is the durability case for paying more than a stock-style replacement.
If you are searching for an FJ60 rear shock upgrade, a 4600 monotube for a stock-height 60 series, or a Bilstein 24-002561 FJ60 rear damper, this is the part built for that job. The manufacturer says it installs like the original with no modifications, and a single axle can be upgraded on its own. Before ordering, check your model year against the manufacturer's lookup. Owners on user forums say rear bushing sizing can vary between FJ60 builds, so compare the bushings on your old shock to the new ones.
Listings disagree on the range, with some showing 1980–1987 and others 1981–1987 or 1981–1983 FJ60 plus 1984–1987 base trucks. Owners on user forums report that the manufacturer's lookup lists 24-002561 as the rear shock for a 1984 FJ60. Confirm your year and VIN with the manufacturer before ordering.
Owners on user forums say the FJ60 and FJ62 shared a similar shock design, but rear bushing size may differ by year. One forum poster suggested that later builds may bolt right on. Compare the bushings on your original shock with the new kit before you start the install.
The manufacturer says the B6 is designed as a direct-fit upgrade for stock-height vehicles and is sized for stock-height springs. For a lifted truck, check with the manufacturer before ordering.
Rated moderate for a home mechanic. The manufacturer's installation instructions call for special tools and expert knowledge, recommend a qualified suspension specialist, and advise using a chassis hoist. Owners on user forums say the rear is cramped and can be a hard job on an older truck. Use jack stands under the frame, support the axle, and let it drop to full droop so the old shock comes off cleanly. Penetrating oil and a puller help with a seized lower eye. On the top stud, hold the shaft with a second wrench so it does not spin while you tighten the nut. Tighten all mounting fasteners before loading the suspension, and replace worn bushings, washers, and bump stops at the same time.
