My 00 silverado Z71 sometimes makes a grinding noise when in 4hi or 4lo when I hit the gas. I thought this could be a CV axle and took it in to have it checked out and was told that the noise was coming from the transfer case. The fluid in the transfer case is full and I didnt get any metal flakes on my finger when I checked the fluid. It almost sounds like gears grinding. Somebody told me missing teeth on the front driveshaft yokecould cause this but when I changed the u joints I didnt see any. Can anyone give me some ideas of what could possibly be wrong?

 

Like actual gringing or more like a rumble?

 

the transfer case would do that all the time...it would change tunes in hi or lo,but it'll always be there..

if this is NOT THERE in 2wd,but ONLY when the 4x4 is engaged,its in the front axle...get away from that shop

 

Thanks for the advice!!! As far as the 4X4 goes it operates, all four wheels pull but it just makes that aweful grinding noise and Im just worried one day Im gonna need it and it wont work or even worse something is going to come apart while Im driving. I am a mechanic by trade for the air force but I dont have any experience in working on 4X4 drivetrains.

 

Check your front diff oil. It could be those gears.

 

Thats another option. Could someone tell me is this a chain driven transfer case in these trucks? Ive never broken one open so I really have no clue!

 

yes,its chain drive...

 

I think thats what made that guy say it was in the transfer case then because it sounds almost exactly like a chain skipping over teeth on a sprocket. I am actually gonna take it to the dealer and let them figure out whats wrong with it because it came with a bumper to bumper extended warranty that goes to 135,000 miles and Im at 108,000.

 

it should do it in 2wd then...but who knows...where in texas are you?lackland?

 

No, Im actually stationed at barksdale Air Force Base in Shreveport La but I will be getting out and moving back home to Splendora, Tx in Aug. Splendora is near the Conroe, Houston area! How bout you I know you said you were in Tx but didnt know what part!