The car has about 15 K miles. I just started getting random clunks and bumps at the rear of my car that sound like someone with a hammer banging around the rear suspension. It sounds like muffled metal on metal, somewhat reminisent of a bad u-joint. However, the sound is not predictably produced on or off the power, turning or not, on the brakes or not. I would have sworn that it was a rear sway bar mount since I put a rear bar on the car a few months back. But I have checked the rear sway bar mounts, rear strut mounts, rear strut bar. The wheel lug nuts are tight and the trunk is empty. Is there any chance this could be the rear diff?

 

if it happens when you're in full lock at low speeds then it could be that your rear diff fluid was changed without a proper fluid modifier.

 

it is possible. My rear diff started groaning with about 25K on the clock.

Symptoms: at low speed, make a tight turn and hear/feel the rear end moan and groan and shimmy. Mine did it both when cold and warmed up.

Solution 1: Changed rear diff fluid with redline ... worked.

3000 miles later started groaning again, but only when warmed up ... back to solution 1 ... 3000 miles later more groaning...

Solution 2: Changed rear diff fluid with Diaqueen Gear Oil (per TRE recommendation) ... so far so good. We'll see how long it lasts.

l8r)

 

Which redline product did you use??

 

I believe it was MT-90, but I'll have to double check when I get home.

l8r)

 

Isn't Redline mt-90 for the tranny???

 

MT = Manual Trans.

 

Do you get this sound when you accelerate and/or speed shift? There's a suspicious clunking sound from the rear when I get on the throttle really hard making hard shifts. I checked the trunk area and everything appears to be stable. It doesn't seem to happen all the time though...

 

As I stated in my original post. I can't cause the noise at will. So, road bumps don't reliably cause it. Getting on or off the gas does not seem to cause it. Turning does not increase its occurence. It appears to be almost random. Although road irregularity may be involved. I have not tested this by going down the same road and noting whether the noise occurs at the same spot every time. I only drive the car on the weekends. So, it is not like I drive the same road every day in a commute.

I said the sound was like a hammer but ist may be slightly more accurate to say it is like a mallet or a blown u-joint. However, if it were this I should be able to duplicate the noise by getting on and off the gas. Playing with the gas does not cause the noise. Turning does not cause the noise. The exhaust is stock and other than a rear sway bar the rear suspension and diff have not been touched. Maybe I'll disconnect one of the sway bar links and see if the noise goes away. It is a simple test. It should rule the sway bar and brackets in or out as the cause of the noise.

 

same here. all was good, changed at 20k with redline shockproof. groaned bad after 500 miles. changed to redline 75w90 and all was good for 4000 miles and now groans on slow 90 degree turns and slow starts from a stop. OEM stuff in the mail.

 

Mine had a really bad chatter when you made tight slow speed turns at 17k miles. I swapped to Redline 75W90 with the friction modifier in it (NS doesn't have it) and almost all of my chatter went away. I guess there wasn't enough of the friction modifier in the 75W90. There was still a slight chatter that you could hear slightly so I picked a 4oz bottle of Redline LSD friction-modifier/ break-in additive and added about 1/2 a bottle and it is now smooth as butter. Here's what the bottle looks like. I hope this helps.

Dave