4x4 issues.

[thewishkah]

Hey guys I am new to the site, I have a 2002 yukon slt with 65k miles that recently started giving me some issues. I started getting a slight scrapping sound from the rear drive shaft on the passenger side that is mostly heard when the truck is decelerating (i.e when i take my foot off the gas and its slowing with out the brakes) also I am having 4x4 issues as well.

If I put the truck into 4wheel hi I hear a clank and then a deep vrrrrr noise coming from the front end while moving. (this noise was not present with the wheels off the ground). I checked the wheel bearings today and they checked out fine no noise and no play in them, I had the whole truck off the ground and put it into gear in 2wheel drive the front tires turned for a few seconds before disengaging (not sure why they would turn in 2 wheel drive).

I then proceeded to go into 4hi and all 4 wheel started turning then the front drivers wheel slowed to a stop and would move like an inch from time to time but would not spin like the rest. It would move freely if I spun it, so its not like it was binding or anything. Does anyone have any idea what may be the cause of this? I was thinking the actuators but I don't think that would cause one wheel to spin and not the other. Also it does the same thing in 4lo. Thanks in advance for any and all information you guys can help me with. I apologize if this is in the wrong section.

 

[WoldD90]

Have you checked your drive shaft u joints? Also, check the fluid levels in your transfercase and diffs.

 

[Freedom Motorsports]

I'm not 100% on this because I can't sit there and listen with you, but it sounds to me as if the carrier bearings in the front differential have given out and are causing the gears inside to not operate properly.

 

[thewishkah]

Not sure about carrier bearings as I have never torn down a differential what is there purpose?

As for the u-joint I'm sure that I have a bad one as it clanks)most noticeably when put into 4lo. I don't think that would prevent one wheel on the front axle from spinning though. The noise in the rear end is centralized to the passenger side any suggestions there?

The issues seem to have gotten worse since having the differentials serviced(fluid drained and refilled). There were small shavings in the fluid but nothing that looked like a catastrophic failure just normal wear over time. The truck is low mileage and I cant believe with 65k it would need new differentials already?

 

[WoldD90]

65K is not a lot, but it seems like it has sat around a lot, and most mechanical things do not like to sit around. Not to mention, you don't always know what the previous owner had done to it.

The clunk when you put it in 4x4LO is normal, mine does it too. But, it sounds like a drive shaft u-joint to me...

 

[Freedom Motorsports]

Your vrrr noise is the pinion gear whining due to lack of proper alignment, this is usually due to a bad carrier bearing allowing everything to drop out of proper alignment inside the diff.

The ujoints are your clunk if it really bad, but SOME clunk going into gear is very common, chevy calls it normal driveline slack.

The issue in the rear is probably the axle seal is blown out and the bearings in that side are shot, I would remove the wheel and brakes and inspect there for grease, there should be ZERO wet looking grease in there. As for the shavings and servicing, I'm not sure putting new fluid in it would have acerbated the situation, but with shavings in the diff housing, you more than likely have had an axle seal and bearings going bad for a while and just didn't realize it and now it has gotten bad enough that you are hearing the bearings grinding on the passenger side. Bad bearings will begin to slow a moving vehicle not under throttle because they are adding rolling resistance.

No 65K isn't a lot, but like stated above, you never know how the previous owner treated the truck, and you should inspect your axles seals, etc regularly to ensure everything is good. They may go for a while before they get bad enough to cause real problems depending on driving habits but it is common for those seals to go out.



Sorry for not covering everything earlier.

 

[thewishkah]

Hey guys the truck has been in my household since new, it never sat for a long period of time just lots of short trips around the city which im sure is an issue in itself. I will check behind the brakes for any leaks and see what I find. As for the clunk its really mostly noticeable going into 4lo other wise its hardly noticeable. How hard would it be to check the carrier bearings? Also for the rear to remove the axle do I need to open the diff? like if I was going to change out the bearing?