4 wheel drive system HORRIBLE NOISE!

nwo · October 30, 2006

Hello All,

This is my first post in this forum. I am hoping someone can help me out.

I just purchased a 1999 GMC Yukon this past Friday. It is in beautiful shape, with all the bells and whistles. It has 153,000 miles on it, and an automatic transmission.

It runs and drives like a dream in 2 wheel drive mode. I decided to test out the 4x system today. When I pressed any of the 4x buttons (4HI, 4x 'on standby', or 4xLO) it engaged, but made a HORRIBLE grinding, clattering noise. When disengaged, the noise stopped. It did this at any speed I tried driving. 4x system engaged, HORRIBLE noise. Disengaged, perfectly fine.

The Lady I bought it from said that she did not use the 4x4 system very much.

What could be wrong, and will it cost me an arm and a leg to get fixed?

I really love my new truck, and am kind of depressed that it has a problem already.

Thank you all, I appreciate it.

nWo

95Sierra2500 · October 30, 2006

I'd start by looking at the front driveshaft, particularly the universal joints, and change any if found to be bad (they'll be really loose and kinda just flop around). It's around $10 for a u-joint and they're dirt simple to change if you have a vice or press and a torch.

I'd then check the front diff and see if there's any fluid in it, and if it needs some top it off (fluid level should be at the bottom of the threads to the fill hole, coming out a bit is okay).

Nice rig · October 30, 2006

Check transfer case servicing as well.

nwo · November 3, 2006

Yep, it's the transfer case. My mechanic checked it out yesterday and today.

That is the main problem (along with a few other problems). It also needs a new starter, a new rear pinion seal, and a new intake manifold gasket set. He is also going to replace the driver side door handle, the hood release lever, and the 4x4 switch.

All this for the low low price of $2000.

I am really depressed right now. I have only had the truck for a week, and I have to pour a ton of repair money into it already. Really depressed indeed.