The wheels are locked together in four-wheel-drive so they are forced to rotate at the same speed. You have one with a smaller tire so it wants to rotate faster than the other three, that will cause a problem? You can get away with that on vehicles listed as "all-wheel-drive". Those have a viscous coupling in the drive shaft to the rear wheels that allows the two axles to turn at different speeds. "Four-wheel-drive" is different. There have been lawsuits over transfer cases being destroyed even when the vehicles had the same size and brand of tires, but one or two were purchased at different times. There can be slight variations from one assembly line to the next that are making the same size and model tire. This has been a big problem with the four-wheel-drive Chevrolet Astrovan's. The people at tire and alignment shops know to only sell tires for these vehicles in matched sets of four. Of course that angers a lot of customers who do not believe this is necessary. It is the same people who bought such a vehicle, and the same ones who look for someone else to blame when the mismatched tires tear up their transfer cases. The problem affects the Astrovan because it is "all-time four-wheel-drive", and can not be driven in two-wheel-drive mode. You will not damage your transfer case if you leave it in two-wheel-drive until you get a set of matched tires.
Sunday, January 8th, 2017 AT 1:03 PM