wierd clacking noise

[cowboy5683]

OK GUYS ..TRY THIS ONE ON FOR SIZE..SURE HOPE YOU CAN HELP...ON THE WAY BACK FROM LAUGHLIN THIS LAST SUNDAY MY BUDDY AND I WERE PLAYING FOLLOW THE LEADER W/ OUR TRUCKS DOWN OLD RICE ROAD(177) AT ABOUT 75 MPH....NOW ALL OF A SUDDEN I HEAR A CLACKING NOISE FROM MY BUDDIES TRUCK AHEAD OF ME..SO FAINT I THOUGHT IT WAS MINE AT FIRST...HE PULLED OVER AND WE CHECKED EVERYTHING EXTERNAL W/ OUR BEST NO TOOL ABILITIES AND FOUND NO LOOSE U-JOINTS OR LOOSE PARTS ANYWHERE...NEEDLESS TO SAY WE TRIED IT AGAIN W/ ME HANGIN OUT OF HIS THIRD DOOR TO KIND OF PINPOINT THE NOISE (GOIN SLOWER OF COURSE) AND IT SEEMS TO BE COMING FROM THE TRANSFERCASE BACK...HARD TO TELL THOUGH... THIS NOISE WILL GO AWAY AND COME BACK, LOUDER AND QUIETER, ON AND OFF THE THROTTLE..SO NO REAL EXACT TIME ...IT IS LOUD LIKE TWO SOMEWHAT THICK PIECES OF METAL HITING EACH OTHER FAIRLY HARD AND QUICK....BUT THE STRANGE THING IS THE NOISE CREATES NO ABNORMAL HEAT ON ANY MOVING PARTS OR ABNORMAL DRIVING AND NO LOSS OF POWER...STRANGE HUH???...WELL IF ANY BODY OUT THERE COULD HELP ..IT WOULD BE VERY MUCH APPRECIATED...BY THE WAY...MY BUDDY HAS A 2001 CHEVY SILVERADO 4x4 W/6" SUPERLIFT AND 3" BODY LIFT...ALSO 37" TSL RADIALS...NO GUESS ON THE GEARS..BUT IT IS GEARED, 'CUZ IT HAS A LOT OF BALLS, TOO MUCH TO BE 3.73'S ...IT WAS BOUGHT THAT WAY...IT IS A SHORTBED TOO IF THAT HELPS.

[GMCTech]

Couple things to check:

 

Did you remove the driveshaft to check the u-joints. You may still have one binding that you tell from just trying to move it up and down on the truck. It has to be taken out and articulated in all directions completely.

 

Also take a quick check at the parking brake shoe. I've seen parking brakes make some pretty strange noises if they start coming apart.

 

And just a note of kindness - Not all capital letters please, it hurts my eyes.

 

Hope this helps.