2000 LS - AWD light no code

I'm starting to go through a 2000 LS AWD I got in December. Among other things, I get the Service AWD light with every 3rd or 4th drive cycle, and it's usually out with the next startup. During the winter, I could feel the AWD engage, but lose it when the light came on. Some times I hear the relay on startup (and the light comes on), but there's no DTC code stored for it.

I checked the fluid on a level surface - it's full (started dripping as the bolt got finger-loose) and it's blue, like it should be. Things look pretty good underneath, though I'm loooking for a way to get it steam cleaned underneath so I can really see everything.

Any suggestions?

harryevan

When was the transfer case fluid changed last? Check your owners manual for the recommended interval. The additives in the fluid deteriorate over time and miles.

Drain it and refill with AutoTrak II fluid, GM P/N 12378508. You'll need 2 liters (it doesn't come in quarts), and will not have any left over if done properly. You might want to make sure your dealer has new drain/fill plugs available, just in case your's are eroded, since the plugs are sacrificial anodes as well as just being plugs. The case is magnesium, and steel plugs are a BIG no-no.

The only maintenance info I got was from CarFax - the previous owner had it into Midas for some rear brake maintenance.

When I checked the fluid, the case (and we're talking about the one on the drivers side next to the transmission as per the owner's manual) looked nearly new, with a red tag from the manufacturer or reman shop and the fluid that did drip out was really clean. If were talking the case on the front axle, looks like that's next.

I'm about to open the engine cover, to replace plugs, wires, rotor and cap, O2 sensors and clean the grime out of the intake. Anything else I should look for first time through?

Thanks
harryevan

You need to change fluid in this case:

http://72.19.213.157/files/AstroAWDTransferCaseMount.jpg

The drain and fill plugs are at the rear:

http://72.19.213.157/files/TransferCasePlugsLg.jpg

A 2000 model year did not initially get a fill with the new (synthetic) AutoTrak II. The "II" formula is fully synthetic.

While you're under there, make sure the electrical connectors are secured to the senors (there are three of them). There is also an electrical connector on the underside for the engagement (encoder) motor.

Since you are removing the dog house, you might consider replacing the distributor cap and rotor (Delco cap ONLY) if the vehicle is closing in on 80K miles or more. You should inspect the ignition coil.

It might also be a good time to remove the air horn and clean the throttle body. Spray-type carburetor cleaner works well for this.

As long as you are getting intimate with the engine, it would be a good idea to check the vacuum line from the LF corner of the intake across the front of the throttle body. This is a small hard nylon line which supplies vacuum to the HVAC controls, and is very prone to cracking and leaking.

Thanks! Looks like a fun Memorial Day Weekend ahead. Can that vaccuum line be replaced with something better, or is it a GM part, only?

BTW, that IS the case I checked, same red tag, similar crayon mark. Surpisingly, it's cleaner than everything else underneath the vehicle. So much so, that I thought it had been replaced or rebuilt, must be in just the right spot.

I found a connector on the forward side of the case that is dangling, but I can't see where it goes yet. I'll send a picture if I can't uncover the receptacle.

Thanks again.


harryevan

Might this help?

http://72.19.213.157/files/TransferCaseCleaned.jpg

Every blue cap (except the front output shaft) is an electrical connector.

Bowtie,

What I've read from threads about the transfer case, they talk about a flush with AutoTrak II, so you're reccomending 4 litres of the stuff, correct?

I was surprised that all the local parts stores didn't stock up for Memorial day, so I picked up a rotor/cap set (paid for the brass), a set of plugs, wires and some 1/8" vaccuum line - opened the cover and took some pics, but I can't attach them yet (forum permissions?) I'll post them as soon as I figure that one out. (Insert Image and a cut and paste didn't work).

I found some fuzzy stuff under the distributor - looks like the first owner's cat liked this spot.

There is a bulbous, wrapped object on the lower A/C line on the left. It's rubbed the isulation off the inside of the engine cover. I don't know if this is stock, or a fix to the line (I guess this line goes to the rear A/C unit?)

On the right side, there is fluid on the back of the head - coolant, I think. I'm wondering if this is the indicator of the intake manifold coolant leak, or something worse, as we go into another 100 degeree summer?

There is damage to the insulation on the upper A/C line that crosses to the right, doesn't appear to be affecting the line, just a cover rub, I guess (A/C works, front and back).

There is insulation (heat?) over the plug wires between looms on the right side, but not on the left, is this stock? Just trying to figure out what's been done. I'm looking for the vaccuum line over the engine.

So, I'm going to clean this up a bit, take care of the throttle body crud and change out the stuff I bought. I'm ordering O2 sensors from Rock Auto (thanks to who ever sent that out), and see what happens.

Thanks for the help, so far.


harryevan