2003 Suburban Z71 Grinding In Front End

TBKHomeworld · November 30, 2007

Howdy all,

First I have tried to search this site and I have found tons of folks talking about grinding in their trucks but nothing that really fits what is happening with mine.

It is a 2003 Suburban Z71 that was purchase about 2 months ago with 69K on it. We use it to tow a pontoon boat and drive around town with the family. I have had to use 4 wheel drive a couple of times pulling the boat into the muddy yard and that has been it (it clunked in the frontend when turning hard in 4HI mode).

Anyway, the truck has started to make a grinding sound in the front end. At first it started when just turning to the left, otherwise it was just fine. This would have to be a left turn that was 40mph+ otherwise no sound. I thought it was brakes so I pulled the tires off tonight planning on doing a brake job and they were in great condition. I put the wheels back on and drove it, trying to figure out the sound.

I put the truck in 4hi, turn left and stepped on it....it began to grind at just 5mph at this point. I put it back in 2WD and now the truck grinds just while driving down the road and it's even worse when turning left.

If you have ever driving a car to the point the pads were gone and it was really metal on rotors and there is a horrible grinding sound....it sounds just like that but a consistent pulse, louder, and worse.

I have checked to see if the tires are rubbing, nothing there. I have looked for cuts in the CV boots and they look fine. This is my first 4X4 so I'm a noob with them but I am very good in the garage. I'm thinking it sounds like an issue with the front differential but I'm not positive.

Can someone please point me in the right direction to try and resolve this issue?

*Crossing fingers for cheap fix*

Thanks a ton!

~TBK

TBKHomeworld · November 30, 2007

I just went and pulled the plug from the front differential and it was CAKED with fine metal shavings. The cake was so thick that it was made smaller in diameter as I pulled it through the threads and it extended 1/4" past the magnet .....if I could have got it all it would probably be at least a teaspoon full of shavings.

~TBK

asilverblazer · November 30, 2007

I don't think that amount of shavings is abnormal for that many miles. I would look at hub wheel bearings, they are much more prone to failure.

Draenor · November 30, 2007

Any metal shavings are bad to me. But I am with Andy, I would look towards the hubs.

Stuff like this is why I am gun shy on buying used 4X4 vehicles.

TBKHomeworld · December 1, 2007

Good call guys. The first time I put the truck on stands to do the brakes it must have been in just the right position because there was no wiggle. Now there is LOT of wiggle on the passenger side.

I have it all taken appart except the retaining bolt for the half shaft.....darned if i don't have a socket big enough for this silly thing!

It appears to be 1 3/8", is that right or is this bad boy metric?

98 Z71 SLT · December 1, 2007

You are still going to have to take your front diff down, and get it rebuilt. You have bad carrier bearings, which will get loud. GM has a bunch of TSB's on this...GM ran into a supplier with a bad batch of bearings.