Philbert47

I'm driving a '97 T100, auto trans, 4x4, with a lever on the floor to activate 4x4. Lever back, 4x4; lever forward 2x4. In 4x4 mode, a light illuminates in the dash cluster. All works as it is supposed to, I think. I am curious how this system works. How does the lever put the front wheels into drive mode, directly or indirectly? Is the dash light switched on by a sensor in the transfer case or simply by the lever? How do I know if my truck actually is in 4x4 mode? Thanks.

the.big.fudge

Search for "solenoid" and the read up on the vacuum system that engages the 4WD. This forum has tons of great info from people who actually know what the heck is going on under the hood. Honestly I barely understand how it works. You should have a 4HI and 4LO, right?

tacobo670

....its a long long story

pretty much, the 4wd shift lever is "mechanical" -like a stick shift transmission, it slides a fork in the transfercase to apply power to the front drive shaft. in doing this, there are switches and sensors that tell several electronic components to turn on (the light) and engage the ADD (via VSV) thus giving u 4WD.
you tube how does a toyota 4wd system work

atcfixer

iTrader: (1)

If it doesn't have ADD the system is a little simpler and the front axle has to be manually locked in via the lockers on the hub, either case the transfer case works the same way, I like how the above poster says it's like a stick shift, seems to be the closest description I could think of too.