When should I lock my 4WD hubs?
Lock manual hubs before you need four-wheel drive. The hub connects each front wheel to the front axle. With the hubs free, selecting 4H or 4L cannot deliver useful drive to the front wheels.
Locking the hubs is not selecting 4WD
Think of it as two switches. The hubs connect the wheels to the front driveline; the transfer case sends engine torque to that driveline. Hubs locked with the transfer case in 2H normally leaves the vehicle driving through the rear wheels, but keeps the front driveline ready.
When can they be free?
For a vehicle that actually has manual free-wheeling hubs, use the manufacturer’s specified FREE/LOCK settings and any maintenance instructions. Do not apply another model’s advice about driving with hubs locked; procedures differ.
The linked Toyota manual is a 1998 US Tacoma example, retrieved during this review. It explains the mechanism but is not an Australian-market operating instruction for your vehicle; obtain the exact owner’s manual before operating the hubs.
Your vehicle may not have manual hubs
Many modern 4WDs engage the front driveline automatically. Do not go looking for a dial that is not there. Read the four-wheel-drive section of your owner’s manual: hub design, shift speeds and required procedures differ.
Follow your vehicle owner’s manual. This guide describes a typical part-time 4WD with manual hubs.