Noise from rear area.

[Super Red]

MKOTZE,

I have a 99' FRC and lately when I am making a turn at slow to low speed, I hear a clinking type sound. This happened once last fall and the dealer's mechanic heard it too. He said it sounded like something was loose or binding in the rear end. He found that two nuts on the rear A-arms were loose and tightens them up, plus they changed the rear end oil per GMs directions. the sound did go away, but now its back again. I had an 87 and it developed what they called "spline snap" in the rear shafts. Could this be possible in the C5? Now that I think about it, the sound is similiar to that sound too. Appreciate you thoughts.

[MKOTZE]

Hello Super Red, Nice car! First off it should not be due to a change in design of the rear suspension. There are several possible causes for the noise when turning. The following areas need to be checked by a service technician. They are as follows: Check the rear axle mount for unusual wear and play, the axle shaft constant velocity joint again for unusual wear, the rear wheel bearing for excessive play and wear, and finally the use of incorrect gear oil. The gear oil has a tendency to wear out and it may just be that it needs to be changed. Here is the correct GM part numbers. 1) 12378261-Synthetic Differential Lubricant, quantity needed is 1.69 quarts or 2 containers. It will also need 2)1052358 Friction Modifier, quantity needed is 4.0 ounces or 1 container. At the very least have them change the oil and add the friction modifier. It should help! Good luck. Corvette Kotze

[Super Red]

Thanks Kotze. I've have them check all the items you mentioned.

[MKOTZE]

Good Morning Super Red, Do I understand correctly that they have already checked everything? What did they say when they checked it? Did they actually change the oil?Let me know. Mkotze

[Super Red]

Hi Mkotze,

Yes, they said they checked everything out the last time and they did change oil and add the modifier. They said GM told them to try this first. Like I said, it seem to stop the noise for awhile, but lately it has began again. I drove it to work on Friday and I could heard the noise every time I made a turn at low speed or backup. Oh, I forgot to tell you that i have lowered the car about 1.5" all around and replaced the stock sway bar end links with GM Z06 units. Appreciate your help!

[MKOTZE]

Hello Super Red, I realize that you had it checked last fall But have you had it checked and the oil changed recently? I also would like to know How many miles have you put on the car since the oil was changed? If the oil has not been changed recently I would recommend starting there. After the oil is changed pay particular attention to the noise. If it went away then we know the problem is internal to the differential. Continue to monitor the noise if it comes back in a short time period then it could be a problem with the positraction clutch pack. If the noise does not go away when the oil is changed then we would go back to the original check list and have them recheck everything thoroughly!Let me know what happens? MKotze:)