can you add a selector switch to a 2000 awd?

[2000 Astro awd]

I've got a 2000 Astro awd that I want to add a selector switch to, to actuate the 4 wheel drive on demand. Is this possible?

[LiftedAWDAstro]

It hasn't been done because there is a variable clutch in there that the TCCM controls. It is not simply on/off. Depending on the amount of wheel slip it will load the clutch more or less when it engages. About all you can do is disable it with a selector switch for RWD only.

[2000 Astro awd]

I don't want to disable it. It goes into 2wd just fine. My problem is that it doesn't always shift the tc when I need it, like if I'm going up hill in the snow it won't always shift in so I'll back off the gas then go again until it finally shift into awd. Thank you for your help :-)

[Drummernaut]

I would follow Lifted's advice. The signal to the motor is pulse modulation. Although there are times when it is straight 12VDC, those time only last long enough to bring the wheel spin difference closer so the modulation will kick back in. http://www.rsgear.com/articles/2006_02.pdf

The TC can switch to 100% duty cycle in 76ms(.076s) so you should not have to back off on the gas.

Do you get an AWD light when your rear wheels spin?

If your TC is not engaging and you have no AWD light, you may want to check or change your fluid(Auto Track II) or it is possible you clutches are starting to wear. TC encoder motor could be weak but usually they just die.

The best option I have seen for manual control of these TC's is what LiftedAWDAstro did: viewtopic.php?f=58&t=8913

Even though he used a 233 you can do half of this with the 136.