2003 4wd problems

[sundayfunday]

Was running in 4wd at about 45 on slick roads when a awful squealing started coming from under the drivers floorboard. Took it out of 4wd and the noise stopped instantly. When driving at very low speeds if I try to activate 4wd it seems like something is trying to lock up. I think it's something in the front diff. Didn't sound like it was coming from the transfer case. Any suggestions?

[chevrolet1616]

Is this 4wd auto? Or 4wd hi? If its 4wd hi, the front axle has a vacuum locker. You should never run in 4wd hi on pavement even when its wet, if you go around a turn at high speeds you are placing the front axle and transfer case under a tremendous load. That whining was probably from your tires scrubbing though.

[sundayfunday]

It was 4wd hi. I was on ice. It's definitely a metal on metal sound Not just tire scrub.sitting in the driveway if I engage 4 hi I have to get about 1500-1800 rpm to make the truck move and occasionally I can hear a grinding noise. Something is acting like it's locked up.

[sahls01gmc]

If you hear that under the drivers seat, that's your transfer case. You can try unhooking the front drive shaft and see if it still does it in 4HI.

[sundayfunday]

It was to far forward to be transfer case issues. Definitely from the diff area. In the process of replacing front u joints now hoping it's something simple. Leaning more to pinion bearing however

[chevrolet1616]

What about a hub bearing?

[gmtech4]

Wrong forum

[gmtech4]

It was to far forward to be transfer case issues. Definitely from the diff area. In the process of replacing front u joints now hoping it's something simple. Leaning more to pinion bearing however

You are on the right track,pull the plug and and check the oil , you'll know if it's the frt diff with the oil condition ,

 

Check t case level and condition also for giggles

 

To Chevrolet1616 , there is no vacuum anything on this trucks 4wd system

 

Is this 4wd auto? Or 4wd hi? If its 4wd hi, the front axle has a vacuum locker. You should never run in 4wd hi on pavement even when its wet, if you go around a turn at high speeds you are placing the front axle and transfer case under a tremendous load. That whining was probably from your tires scrubbing though.