LOUD clunk turning in 4wd

[lkrasner]

2002 Tahoe 4x4 5.3 flex with 280k miles.

Had the first snow of the year today, so I decided to put the truck in 4wd just to make sure everything was working. The parking lot wasn't totally slick, so I expected some normal tire drag pulling out of the parking spot, but instead got a horrible clunking noise. It felt kind of like something in the front differential was slipping, if that is even possible.

It does it whenever making a hard turn in 4hi or auto when it has engaged the front wheels. Any ideas what this could be?

 

[ccapehartusarmyINF.(ret)]

was the parking lot covered in snow or was it just a bit damp
are we talking one clunk or every time you turn hard
what kind of surface are you one when you make these hard turns
i always avoid hard turns unless im in snow icy or muddy conditions i hesitate even on loose gravel

 

[lkrasner]

was the parking lot covered in snow or was it just a bit damp
are we talking one clunk or every time you turn hard
what kind of surface are you one when you make these hard turns
i always avoid hard turns unless im in snow icy or muddy conditions i hesitate even on loose gravel

It was mostly just wet, definitely less slick than I would normally drive in 4wd on, but I've never experienced anything like this. Even normally driving there was a bit of a growl when accelerating and turning. Nothing it's ever done before, which is why I am concerned.

 

[ccapehartusarmyINF.(ret)]

maybe drain it and change the diff lube and pay attention to the drain plug its a magnet see if any pieces of metal are stuck to it or shavings

 

[SLCHOE]

Check your front driveshaft U-Joints. Grab ahold of the shaft and shake it up/down and l/r. The u-joints should be tight and you should have no movement.

 

[ccapehartusarmyINF.(ret)]

yes do what SLCHOE said to
also find a big muddy area or a muddy road or snowy area what ever the case may be just make sure its real slick and do some hard turns in there and see if the same thing happens

 

[lkrasner]

Check your front driveshaft U-Joints. Grab ahold of the shaft and shake it up/down and l/r. The u-joints should be tight and you should have no movement.

U joints feel solid to me.

yes do what SLCHOE said to
also find a big muddy area or a muddy road or snowy area what ever the case may be just make sure its real slick and do some hard turns in there and see if the same thing happens

It only makes the bad clunking/ gear slipping sound when it is fairly dry. if it is slick, it's fine. There is still more noise in the drivetrain than their should be in 4wd though no matter what. If I have it in auto, I can hear it kick in very easily and it growls while accelerating

maybe drain it and change the diff lube and pay attention to the drain plug its a magnet see if any pieces of metal are stuck to it or shavings

how hard is it to drain and replace the fluid? I'm off at college right now and I only have access to basic tools.

 

[ccapehartusarmyINF.(ret)]

so if it only does it on fairly dry surface then its possible that you may have chipped a few teeth or tooth off yer ring or pinion gear
there is a drain plug at the bottom of the diffs both front and back
it mite be wise in yer case to go to a lube shop and have it done shouldnt be expensive
if there is any chunks of metal stuck to the drain plug that would be the confirmation

 

[lkrasner]

so if it only does it on fairly dry surface then its possible that you may have chipped a few teeth or tooth off yer ring or pinion gear
there is a drain plug at the bottom of the diffs both front and back
it mite be wise in yer case to go to a lube shop and have it done shouldnt be expensive
if there is any chunks of metal stuck to the drain plug that would be the confirmation

This is what I was fearing.

I just changed the fluid, took like 5 minutes, super easy job. Old fluid looked decent enough, bit of a burnt smell to it. It seemed like I took out a bit less than I put in though, maybe by a quarter to half quart. The plug magnet didn't look bad though. some metal shavings, but no larger pieces (see picture below). Drove it again and it did the same thing. bit loud driving straight, the tighter I turn, the louder the low pitch grinding gets, the sometimes when really turning and fairly dry surface it clunks and lurches through the turn.

I really don't want to keep testing it, since That must be doing some kind of damage and I really don't like to drive it in 4wd on dry pavement anyway. Could it be something in the transfer case? I was thinking it must be diff related since it gets worse with the turns and only happens in 4wd.

 

[Mr. 960]

IDK what you are testing is exactly what you are not supposed to do! Make hard turns on dry pavement. search up youtube under south main auto. Erick O had a S-10 with the same exact symptoms. Turned out to be a messed up transfer case.