: Cluck sounds and vibrations from driveline???



spl explorer
12-06-09, 05:52 PM
I have really bad vibrations and clunking sounds from under the car. I'm suspecting that the Differential bearing is causing this... How to I replace or check this part? I replaced both U joints but that didnt solve anything...

jayoldschool
12-06-09, 07:26 PM
It's probably the U joints on the driveshaft. Get it up in the air, and grab the driveshaft. Move it back and forth and twist it and check for play in the joints. Easy and cheap to change...

Stingroo
12-06-09, 08:18 PM
But he's just replaced them?

spl explorer
12-06-09, 08:43 PM
I replaced the rear one. The one closest to the tranny looked to be in good condition so I left it. Dont really know why though. Should have just replaced that too

jayoldschool
12-06-09, 08:50 PM
Ooops, read too fast. Did you mark the driveshaft? If not, take it out, and put it back in 180 degrees. I would do that other joint, though. Make sure that one of the caps didn't come loose...

spl explorer
12-06-09, 09:49 PM
Ooops, read too fast. Did you mark the driveshaft? If not, take it out, and put it back in 180 degrees. I would do that other joint, though. Make sure that one of the caps didn't come loose...

Thanks ill take a look. 180 degrees? What, rotate it? Its sormy here in Cali for the next few days so ill have to wait a bit but what should I look at if it turns out not to be the other U joint?

05devilledave
12-06-09, 10:08 PM
The last time I heard a "Cluck" from the rear of my Caddy is when I nearly ran over one of my chickens. He bolted to the hen house like greased lightening. LOL, seriously though. Chock the front wheels and get the rear tires off the ground with jack stands. rotate the drive shaft back and forth in short increments and watch the rear wheels, if there is a delay between you turning the shaft, and then the wheels turning, with a clunk sound, then your differential maybe shot. I bet the ring and pinion gear have too much mesh due to wear. The repair for this is not a backyard mechanic repair. You will need to have a shop do it. If you dont get the pinion crush collar just right, and the mesh just right, you will have clunking again, or worse, too tight, and rapid wear.

jayoldschool
12-06-09, 10:25 PM
180 degrees? What, rotate it?

Yes. Take out the driveshaft after you mark it, and put it back in exactly opposite.

Check your trans mount, too. I doubt it is the rear diff. These cars don't have enough power to hurt them...

csbuckn
12-06-09, 10:48 PM
I was thinking the tranny mount. I had a bad one and, if I hit the gas hard enough, it would come up and hit the floor pan.

05devilledave
12-06-09, 11:01 PM
It is possible that alot of his diff oil has leaked out from a bad pinion or cover seal, and what little oil is left, is burned and filled with debris. Any rear end will go out quick with low or no oil. A tranny mount will cause clunking, but at times could be felt through the tranny tunnel as it impacts the top of it during heavy acceleration or put into gear. I guess time will tell

spl explorer
12-08-09, 07:24 PM
Been in the low 40s here in Cali. Not used to it so ive been to lazy to get out there in the cold and start working on it. But one thing I forgot to say is that along with the clunk sounds there is a clack clack clack sound at low speeds...

sven914
12-08-09, 08:15 PM
But one thing I forgot to say is that along with the clunk sounds there is a clack clack clack sound at low speeds...

That sounds like the rear differential. A worn rear diff will make clicking sounds at slow speeds, and if there is too much play in in the gears, they will clunk when the car is put in gear. Drive shaft universal joints will make more of a high pitched squeaking sound when the car is driving.

You can check the differential by unbolting the rear cover and looking at the fluid to see if there are any metal shavings floating around.