onebad928s

ok i know its been posted a few times but lets see what if we can break this down. From the rear from what its seems to be coming from as i drive theres a nock. When you accelerate it goes away, when you put the car back on the ground after jacking it up theres no noise until it seems the car settles to correct height. I tried the push in the clutch a little trick and nothing.The parts that were changed so far are: axles (cv),rear hub bearings (advise everyone to do them, the upgrades are great) and rear diff. The car seems to drive fine except the noise and i didnt notice any fresh metal marks any where under the car from rubbing. All hardware was retorqued. Any suggestions?

Lou
83 928 5speed

toofast928

Lou did you inspect the rear trans mounts, trans axle carrier mounting? The knock occurs only on deacceleration, coasting. Hear it once or repeated during the drive.

Tony

onebad928s

i hear it during coasting or when my foot is off the pedal, even if its in gear. All mounts look good and the sound happens all the time not just once in a while.

Lou
83 928 5speed

toofast928

So in your post axles have been repl. That means inner and outer CV too?. How about the E Brake hardware. A worn hold down spring could allow the E Brake shoe to "knock" on the inside if the drum.

onebad928s

No e-brakes, all the items were removed when i did the hub bearings including the cables and handle

Lou
83 928 5speed

AO

When you say all hardware was re-torqued, what do you mean by all? The things that come to my mind are, drop links, main pin for rear suspension (goes through bottom of strut), top nut on strut tower, Rear sway bar, maybe even the splash shields.

Maybe it would help if you gave some more details. Was the sound there before you replaced the items you listed? Is it dependednt on speed (faster you're moving - the often the noise). Do you hear it in reverse? Is it more prevelent in any particular gear/neutral? Do you hear it under braking? The more details the better we can help.

onebad928s

ok Andrew lets see, all hardware includes: axle nuts to the diff,main axle nut by rim bottom rod if you want to say that goes through lower arm and hub and shock. The sound is more like a rubbing sound or a click if you want to say. The only time it does not make the sound is when im giving it gas or i go for a ride after the car is lowered to the ground after its on the jack. Nothing else would seem to be clicking or atleast showing to be clicking unless the torque tube bearings are starting to go perhaps, maybe


Lou
83 928 5speed

blau928

I had a clunk when starting from a full stop, and when stopping just before a full stop.. It was my Torque Tube... I have just replaced the TT & Trans, and same axles.... Knock gone... zippo, quiet, nothing.. I also had the TT humming like a wailing hyena or a grumbling ox, but now that's all silent as well...

I have a clunking sound from my left front suspension when the wheel is turned full lock right, but I think I need to replace the left upper A Arm...

Are you sure it's from the rear...?

HTH,

onebad928s

its only the rear since i only have jacked up the rear a few times to see if i noticed any wear out marks, i also had the car on jack stands and put it in gear to see what it could be but at that time once again the noise stopped until it was back on the ground.

Lou
83 928 5speed

toofast928

So Lou its a one time knock noise when you let off the throttle or is it a repeated knock? Broken tooth off a gear in the trans?
Sounds like your gonna need electronic ears, the ones that have several 10ft leads so you can clip onto different parts of the underside while you drive and pinpoint where the knock is.

AO

What you've described is this:
Power related (only heard under power - not coasting)
Only occurs after suspension has settled
More of a rub/click, than a thump
And you're pretty damn sure it's coming from the rear

You still haven't answered if it's speed related, RPM related, or constant. New sound since your R&R or same old problem. One time or continuous. Also, do you hear it in all gears including reverse? You really should answer these questions so we can help you rule other things out/point you in the right direction.

When was the last time you checked your trans oil? Did you check it, or have someone check it for you? When was the last time it was changed?

onebad928s

ok lets see:
the noise is constant when the car settles at all speeds and gears except for when the car is given gas. Fluid in the rear was checked toward the end of the summer when i blew the original rear and so far the housing is dry and car has only been driven maybe 20 times since the summer.Im pretty sure the sound is coming from the rear because as i said after the rear settles as its the only thing i jacked up then the noise starts. If i push in the clutch (5 speed not auto)the noise is still there. The car Does not shake or shimmer when noise is in progress and the car drives no different. The car is just a pain in my *** right now and being difficult....LOL


Lou
83 928 5speed

toofast928

Man you blew the rear?
Sounds like the ring and pinion are not set up correctly. If the gear set is changed. Then the end play to the main shaft changes and must be adjusted with a shim. o much end pay in the trans could be the noise also..........

onebad928s

toofast........yes last summer i blew the rear, the main rod that holds the spider gears cracked and caused the gears to lodge themselves to give me pure posi. The gears are now replaced with a LSD and ill tell you one thing, im not sure what year the LSD was for but it seems to be a high torque limited slip. No matter the road condition i still smoke the 315s, even if you jack the car up and spin one tire the other spins in the same direction almost as a pure posi would. Well i guess when its a little warmer out ill drop the exhaust and shield to get a better look at the torque tube and its connections. Also i know the sound your talking about if the gears werent shimmed right, it would be a humming sound but like i said the car doesnt run or drive any different except for the friggin noise.

Lou
83 928 5speed

AO

Well Lou. Obviously hard to pin point this one. I would suspect the parts that have been messed with, then the TT. Maybe you can get a friend to strp themselves to a creeper while you drive (a la SPEED) and see if they can hear where the noise is coming from. (I'm kidding of course!) Hope you can track it down.