I have a 2000 Astro AWD. Love the thing to death, but having problems with the AWD working when it should.
Most of the time in wintery weather driving, I am fearless as to the conditions of the roads, as the van feels surefooted.
On occasions, like at a stop light, when taking off, and turning the corner, the rear end wants to come around. This tells me the AWD isn't working.
Last weekend, at a friends, I had him watch the front wheels when taking off on his icy driveway. The first time I tried it, the AWD kicked in. Twice after that, it didn't.
Last night the same thing at my brothers. No AWD, just 1 rear tire spinning.
Most will say its the encoder motor, and I tend to agree, but has anyone had one that would work at times?
Being intermittent, should I be looking at something else before I change out the encoder motor.
Any ideas, or advice would be appreciated.

 

The encoders in the front wheel bearing housing can get dirty. May be hard to check.
Make sure all the tires are of fairly equal tread wear.
The AWD kicks in from a small motor next to the transfer case. May be easy to check.
And of course all the signals have to be processed in a control module or maybe the main computer.
Good luck.