AWD?

[frw]

This may seem like a stupid question, but I am going to ask it anyway. I just recently bought an 02 AWD Astro, and was wondering about the AWD unit. Is it full time AWD like my wife's Land Cruiser where all 4 wheels are engaged at all times, or is it like the AWD setting in my Tahoe where the front wheels are only engaged when there is slipping in the rear (unless I have it in 4Hi or 4Lo)? This is not an earth shattering issue just curious. I am guessing by the steering feel it is like the Tahoe, i.e two wheel rear most of the time with the fronts only pulling when needed.

[betz]

Yes, the AWD on your Astro is setup like the AWD on your Tahoe. When the rear wheels slip, the AWD is electronically engaged.

[timelessbeing]

What about the 2000 model?

[betz]

Yes, the 2000 model is also the same. It was either 97 or 98 when they switched to the electrical engagement method. Previous to that it was mechanically operated and always putting power to the front wheels.

[frw]

Thanks that is what I thought but just wanted to be sure.

[timelessbeing]

I've heard different stories as to when they switched the Astro transfer cases from viscous-coupled to electronic. I've heard anywhere from '97 to '02, so what is it? Will any of my RPO codes indicate what's being used?

[timelessbeing]

Found this snippet on Consumer Guide:

1999 Chevrolet Astro: Astro's all-wheel-drive system was revised so that power was only sent to the front wheels when needed for maximum traction. Other changes included a standard overhead console on LS and LT trimmed models.

http://consumerguideauto.howstuffworks.com/1990-to-2004-chevrolet-astro.htm

EDIT: Just checked the tag on the unit itself and it's an NVG 136.

[timelessbeing]

And here is a schematic and description of how the New Venture Gear 136 works:
http://www.gminsidenews.com/forums/1311746-post2.html

[creativers]

I have a 1995 AWD Safari. We got hit with a heavy late snow last month, so I tried out my AWD on our steep driveway. It initially had better traction than our new AWD Ford Edge, but when I stopped, then gunned it, either the front or rear wheels would spin while the others sat there. So apparently there is no posi-traction mechanism in the differential (what is this called?) between the front and rear. Is that expected?

[ScottS]

I don't think it is supposed to work that way and it makes me think your fluid needs replaced- but I am doing some research

Interesting article on AWD- I did not know the AWD on the Astro/Safari was made by FF

also found this



http://home.comcast.net/~eliot_www/awd.html

and unrelated but really inetesting- this

http://www.hptuners.com/forum/showthrea ... 225&page=2

[creativers]

That is a very informative article. I've heard some of the words kicked around before, but this helps. Thanks.

[mystrovan]

Hey there creativers. You were saying on a snowey slope one front wheel breaks loose and a rear wheel too, thats normal if you don't have any positrack differentials. Once one on the back and one on the front slip it just sits there like a two wheel drive! Mines the same. The trans-case is doing its thing to send power to the front too, obviously you have seen one front wheel spinning, but beyond the trans-case it can't make anymore wheels grab if theres no positrack.. I had a F**D Aerostar ( ) once, it was 2WD and it had possitrack in the back and I loved it. It ploughed through snow like a tank. Not saying my astro don't....just keep the momentum up!