To prevent an engine stall caused by a sudden lowering of driving force due to shift-up and a sudden speed decrease by checking a 5-speed shifting rod from being shifted up to the 5-speed state when a high-low shifting rod is positioned in a low range during 4-wheel driving.

In a transmission where a two-wheel drive.four-wheel drive shifting rod 76 and a high-low shifting rod 78 are disposed, a 5-speed shift interlock pin 86 is disposed between a 5-speed shifting rod 66 and a high-low shifting rod 78 in 4-wheel driving, and there is provided a 5-speed interlock means 88 which has the 5-speed shift interlock pin 86 and checks the 5-speed shifting rod 66 from being shifted up to the 5-speed state when the high-low shifting rod 78 is positioned in the low range during 4-wheel driving.