Are they not the same thing? Does and all wheel drive apply to vehicles with more or less than 4 wheels?
In: Other
Generally speaking, AWD is permanently engaged. It’s safe drive with it engaged all the time because there’s some mechanism that allows the front and rear driveshaft to spin at slightly different speeds when turning, such as a center differential, or a clutch pack that really only engages the second axle when it detects wheel spin.
4×4 or four wheel drive is manually selectable. If selected, both driveshafts to the front and rear will be driven at the same speeds. It’s not safe to drive with this engaged on a hard surfaces because the drivelines will need to spin at slightly different speeds when turning. The front driveline will need to spin slightly slower than the rear when turning. If the surface is slippery, the tires will slip just enough to keep the driveshafts from binding. If you drive with 4×4 engaged on a hard surface, turning will bind the front and rear drivelines at the collar in the transfer case, and could cause damage or weird driving characteristics.
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