Hello all! I'm brand new to posting here except that I've been lurking for about 2 months now. I got a couple questions pretaining to 4x4. I just got this '97 chevy blazer with the 4.3 and automatic transmission after I had a Ford explorer so I'm familier with 4 wheel drive, Just not Chevy. Anyways, I live in Colorado and it snowed the last three days and It's a real icy heavy wet snow making the roads very slick.

1. Very bad vibration at around 30MPH+in 4x4. Below is fine. So bad that I cannot have it in 4 wheel drive if I want to drive above 30MPH. Seems to be coming from the front but I cannot tell. Dosen't seem to come from below me where the front driveshaft is. This is the biggest issue. I thnk it maybe a front axle half-shaft but I don't know these symptons.

2. When I'm moving and I hit the 2wheel drive button, the front vibration dosne't seem to go away, unless I totally stop, put it into 4wheel drive and then drive forward about 10 feet, and then stop and then put it into 2 wheel drive. My question is, it dosen't seem to disengage from 4 wheel drive while moving unless you totally stop and start over or even reverse the vehicle. Make sense?

3. Engaging and disengaging from 4hi. How should I do this? Stop and push buttons or can I be moving, say 25MPH+?

4. The push button. Should the 2wheel drive button light up like the 4 wheel drive button once pushed?

5. Coming up a hill and then stopping for a moment, I get this smell, like a rubber burning type smell, or at the very least a hot smell of some sort, but only when I'm in 4 wheel drive. It seems to come from the driver side but I cannot tell where. No smoke. Just a smell.

6. Lastly, what kind of issues have others had with the 4 wheel drive, so I have and idea.

Any help will be appreciated. I really need to get this fixed as it's my 4 wheel drive were talking about here. Kinda important up here. Thank you!

 

Welcome to the site, it sounds like most of your problems are comming from the front differential. I would make sure that someone hasn't changed the diff with a different gear ratio. I say this because the noise only happens in 4WD and there is a problem getting it out of 4WD these two problems CAN be caused by the tires turning at different speeds (different gear ratios or different size tires front-to-rear). There are only a few parts up front that spin when in 4WD that don't spin in 2WD and the axles are not one of them, they are splined to the wheel hubs, so they turn whenever the wheels turn, therefore I would say it's not a halfshaft making the noise. It could be the front driveshaft, front ring or pinion gear or bearing, or side gears or bearings on the front diff carier (internal parts of the front diff.).

This system is designed to shift from 4HI to 2HI and back at ANY vehicle speed. You can only shift to and from 4LO with the transmission in neutral and vehicle speed UNDER 5 MPH. The 2WD indicator does light up, but it only lights at about 1/2 of the intensity of the other buttons when selected. I hope this helps.

 

Thanks for your reply and welcome. Well, the switch does not light up for the 2wd button. Only 4wd buttons. I think the switch light is burnt out. I did notice that today there is a smaller vibration coming from the front of the vehicle in 2wd only. It's nowhere near as bad but it is there. Feels like the same vibration only 3/4 of the intensity of the 4wd vibration. If it was a halfshaft, would the vibration be there in 2wd and then get worse in 4wd because the transfer case would be sending power to the front wheels?

 

you're welcome

yes probably a bad bulb.

yes it would get worse (probably) in 4WD

 

I will play around with it and see if I can find a problem. Thanks for the help so far! [8D]

 

The 4 wheel drive works fine now except for the fact that it goes right into 4x4 when you press the 4hi button. The problem is trying to get out of 4x4 when your moving. You have to completely stop the truck and then reverse the truck until it goes out and back into 2hi. Kinda sucks when you have to do that. It's like old-skool now. Any ideas on this?