Diff noise? - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

albl · 05-18-2003, 02:50

Hi All,

I started noticing a hard knocking noise from the rear axle area closer to the driver's side. It's a single knock that appears when:
1. I take off harder;
2. Release the throttle;
3. Get off the turn at higher speed.
It used to do it only in wet weather but now I can hear it even when the road is dry., though less frequently.

My car has LSD being Fairmont Ghia and I assume that the sound is coming from the diff but it could as well be the right rear wheel.

I would appreciate your thoughts what could it be.

Regards,
Alex

mongrelEB · 05-18-2003, 04:15

Check your suspension bushings.
Mine was doing this not long ago, it turned out that a combination of repeated hard launches and too-low suspension (scraping) had knocked off one of the bolts holding the stabiliser bar onto the diff.

albl · 05-18-2003, 04:25

Thanks MongrelEB,

I will check it tomorrow. I have stock suspension hight and rear springs and shockers replaced about 4 months ago.

Regards,
Alex

snavy · 05-18-2003, 08:47

i always wanted to know about bushings! From my understanding its the rubber bits between two metal bits connecting together right?

if so how do you know if they are stuffed or not?

thanks

Martin · 05-18-2003, 12:20

Quote:

Originally posted by snavy

if so how do you know if they are stuffed or not?

thanks

Easy, anything more than 150k kms on Aussie roads and you can pretty much bet they're past their used by date. (When talking about rubber bushes)

SiX_iN_a_RoW · 05-18-2003, 17:13

They become brittle, crack and pretty much fall apart

After you had the new suspension put in, did you retighten all the bolts after a few weeks? because once the bushes settle and squash a bit they usually need to be nipped up a little. Check the top shock absorber bolts first

albl · 05-18-2003, 23:56

I tried it today in dry weather and it didn't knock at all. So it seems that wet road makes a major contribution to the knocking.

I'm a bit puzzled, could it be the sound of LSD engaging? And it only engages when the road surface is wet?

Regards,
Alex

WBT56 · 05-19-2003, 03:06

Quote:

Originally posted by albl
could it be the sound of LSD engaging? And it only engages when the road surface is wet?

Most BW LSD hemispheres have a ridge in the bottom of the housing. When the cones wear to a certain point they bottom out on this ridge and stop working. This leaves insufficient friction for the cones to load up properly and they can release with a sharp "clack". Will generally occur in situations when the LSD is working harder, ie poor traction on one wheel. Cheap fix- put SAF/XA in it to disable the LSD and shut it up. Proper fix- get a driveline specialist to rebuild the hemisphere.