Transmission clunk noise every time I let off clutch

KDWHELAN

MEMBER
1993 GMC SIERRA
160,000 MILES

My 93 Gmc K1500 4x4 extended cab 5.7 LITER manual Transmission has a clunk noise every time when I let off clutch. It also does it if I hit a good size bump. My rear end went out so I bought a used one and put it in and also have changed both u joints on main drive shaft. Not sure if its coming from differential or one of my rear brake drums. When driving down the road in a steady gear it sounds good. What should I look for or what steps do I need to take to figure it out. Also there is about 3/4 to about an inch of play in differential.

6 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Check u-joints

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Saturday, February 4th, 2012 AT 1:33 AM

KDWHELAN

MEMBER
8 POSTS

Ujoints are good. What else u think.

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Saturday, February 4th, 2012 AT 1:42 AM

CJ MEDEVAC

MECHANIC
11,005 POSTS

HOW MUCH ROTATIONAL SLOP IS IN THE DIFF. CW AND CCW?

IT SHOULD BE VERY LITTLE. LIKE MAYBE A SLIGHT RATTLE IF YOU GO CW-CCW OVER AND OVER.I HAD A JEEP ONCE THAT HAD NEARLY A 1/4 OF A TURN, IT WAS SUPPOSED TO HAVE BEEN A "STANDARD"--I FOUND OUT LATER, AFTER USING THE WRONG JUICE IN IT, THAT THE CLUTCHES INSIDE THE CARRIER WERE WORN SLAP OUT.

DOES IT DO THIS IN REVERSE?

ANYTHING WHEN GETTING ON THE GAS OR OFF OF THE GAS. DOWNHILL COASTING. UP HILL COASTING. ETC?

DID YOU INSPECT THE BRAKES?

DO THEY OPERATE CORRECTLY?

DO YOU FEEL PULSATIONS WHEN BRAKING?

DOES IT DO IT BRAKING FORWARD?

WHAT ABOUT BRAKING IN REVERSE?

DID YOU RE-INSPECT THE U-JOINTS.I HAVE SEEN WHERE PEOPLE DO NOT GET THE CAPS SEATED (SORTA SITTING ON THE LEDGE) THEN THEY WORK OUT AND ARE NOW SEATED BUT LOOSE.

WHY DID YOU REPLACE THE REAR AXLE? GREAT DETAIL PLEASE!

IS IT THE SAME RATIO AS THE FRONT?

FULL OF THE CORRECT JUICE?

ARE YOU SURE YOU ARE NOT IN 4X4?

POSSIBLE THAT ONE FRONT HUB IS HUNG UP, WILL NOT DISENGAGE?

MAYBE SOMETHING IN THERE WILL JUMP OUT AT YOU!

YOUR TURN

THE MEDIC

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Saturday, February 4th, 2012 AT 4:01 AM

KDWHELAN

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8 POSTS

I changed the rearend cause the pinion gear broke in pieces. I just did a front break job and I checked the rears when I put the rear axle in about a month ago. There is about a quarter to half inch play in differential. Yes same ratio and correct juice. When breaking it does pulsate a little but not as bad after I changed front break pads.

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Saturday, February 4th, 2012 AT 4:40 AM

CJ MEDEVAC

MECHANIC
11,005 POSTS

WAS THE PINION NORMAL WEAR AND TEAR OR WAS IT DUE TO EXTREME H. ELL DAMAGE?

IS IT POSSIBLE THAT THE DRIVE-SHAFT TORQUED AND TWISTED (EVEN SLIGHTLY)?

A POSSIBLE QUICK (NOT SUPER ACCURATE) WAY TO CHECK IS WITH A "PLUMBERS TYPE" TORPEDO LEVEL---GET ONE OF THE CAPS (YOKE HOLDING THE CAP) OF THE U-JOINT AT THE DIFFERENTIAL OR TRANSMISSION. EITHER "PLUMB" OR "LEVEL" (VERTICAL OR HORIZONTAL) WITHOUT DISTURBING IT, CHECK THE OTHER END OF THE DRIVE-SHAFT YOKE TO BE "PLUMB" OR "LEVEL"

NOT TOO LONG AGO, I SAW ONE W/ A BARELY NOTICEABLE SPIRAL LINE OR WRINKLE IN THE FULL LENGTH OF THE DRIVE-SHAFT SHAFT. CAUSED FROM REPEATED ATTEMPTS TO JERK A STUMP OUT

IT SORTA "CLICKED" AS IT TURNED OVER. UNIVERSALS BINDING ON EACH OTHER

IS IT POSSIBLE THAT YOUR U-BOLTS ARE ALLOWING THE REAR-END TO ROTATE?

MAYBE A TEST WOULD BE PAINT A LINE ON THE U-BOLTS AND ON THE AXLE HOUSING TOO---LOOK AT THE LINES AND SEE IF THEY SEPARATE OR BECOME MIS-ALIGNED FROM TIME TO TIME?

YOUR TURN

THE MEDIC