I have a 03 Silverado with Autotrac and the front axles will not engauge in auto 4x4, 4hi, or 4lo. I can hear the tranfer case shift, and it does sound much louder then my friends Silverados, so not sure if I should be able to hear it that loud. I do have 92,000 miles on this rig.

Any thoughts or know problems with this system? I did un-hook the battery and hook it back up, plus check the 4x4 fuse under the hood.

I hope it is nothing expensive.

I'm not sure what it is, but all of my relatives who have or had Silverados, including my dad's work truck, have had problems with the 4x4 system. They range from the years 2000 to 2003. I'm not sure if it's the same system, but my parent's old 2000 Blazer's 4x4 system stopped working a few different times and I think it was always a vacuum switch that was the problem.

Sounds the vacuum actuator. They are known to go bad at that mileage. You can convert the system to a cable operated one for a couple hundred bucks and never have to think about it again.

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Same thing went out in my 03 Suburban right after I bought it, the dealer replaced it.

Vacuum actuator, most parts stores sell them for about 50.00, so they're not all that expensive to replace, but I would go for the couple hundred dollar, cable conversion and not worry about it.

So I would guess you find tha vacum actuator around the front differental?

I really think my tranfer case is fine. I did have the problem with the switch always showing the thing was in neutral. Dealer reset or flashed it and that worked for a fe weeks. Then back to showing in neutral. So they replaced an encoder motor. Not sure, but I think that makes the tranfer case go into it's different modes.

I should have stuck with my 01 Silverado with the good old lever.

Yeah, Vacuum motor should be located down on the front chunk.

heh...

I like the "Auto 4WD" button so after your already in the ditch it goes into 4wd.

Well, brought the rig into my dealer and they spent 4 hours going over things. Tranfer case is fine, front vacum actuator is working all things on the outside work as they should. They said they had the two best techs working on it. But now they think they will have to open up the front dif.

I'm thinking the private shop that did replace the front axle seal put something back in wrong and that is the problem. I mean after all they are the same shop that told me I needed to spend $4000 on a tranny. 30,000 miles later and all is fine. Plus they told me my brakes pads were ready to fall out. Well after I told them I wanted to see the old pads I got my money back. They had at least 60% left and that was at 70,000 miles. I never believe in using my brakes.

So I will save up for the big pulling the front dif cover and finding out what is wrong.

So about two years ago I had a local shop replace my front axle seal. And yes I never needed the 4wd till a few months ago. So my dealer has been trying to fix it without luck. Well another trip to the dealer and this time I told them about having the local shop replace the seal. Well the tech just pulled the front axle and found that the shop did not put in the thrust washer right, it was just stuck between the shift fork and the case.

I really hate that shop and have started a claim against them with the BBB.

And my dealer was great, they worked on it for 4 hours on the first vist and only charged me $100. But another $100 today.