fump fump fump noise

[pebbles]

hey guys
ive got this consisent noise comeing from the rear of my car
its a ke70 with a stock diff with a welded centre

the noise has prety much been there since i got it and for most of that time the centre was open

i have changed wheels/tyres numerous times, but the noise remains

the axle bearings are still in tact, well theyw ere when the locker was done

the rear left axle seal is broken so abit of diff oil comes out there

but yeah, prety hard to describe, just wondering if anyone had ideas?

slightly bent axle maybe?

[sdm86]

fump fump fump from the read?
magic fullysick sub installed without your knowing ?

[biggo]

center bearings are fucked

i drove on mine for about 6 months like that with no probs buts its only like $60 to get new ones so why not?

[Duurs]

ok, would that make sense if the centre that went in when it was locked was actually different and the only part used form the old centre was only the crownwheel?

Edit: this post by grape_moosha

[biggo]

you fail

have you seen how fast a locker can wear out center bearings?

[pebbles]

i don't really care, was just curious as to what it was

only really notice it when other people mention it lol

[Sketchypip]

does this noise only happen when your turning?

it sounds like what my mates fully sic vl commodore used to do, it was complete with leb spec welded diff did, or "mini spool" as they would have you believe when purchasing from them.

what happens is, when your turning, your rear wheels are still trying to both travel the same distance, when the inside wheel has less distance to travel it skips instead.

this is why a 2 way lsd is choice, because under full load it locks and yet when turning at slow speeds it doesn't lock allowing you to turn normally.

i know you said that your diff wasn't always welded, but then again maybe your just crazy.....lol

[350hp4agte]

<div class='quotetop'>QUOTE (slidn_ways @ May 25 2008, 01:32 AM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=536260)</div>
does this noise only happen when your turning?

it sounds like what my mates fully sic vl commodore used to do, it was complete with leb spec welded diff did, or "mini spool" as they would have you believe when purchasing from them.

what happens is, when your turning, your rear wheels are still trying to both travel the same distance, when the inside wheel has less distance to travel it skips instead.

this is why a 2 way lsd is choice, because under full load it locks and yet when turning at slow speeds it doesn't lock allowing you to turn normally.

i know you said that your diff wasn't always welded, but then again maybe your just crazy.....lol[/b]

I'm pretty sure that 99.99% of people on this site would no what happens when ya weld a diff

its the centre bearing man happens in my car to IN A STRAIGHT LINE around corners any time i just haven't cared to change it yet

[ae71]

i just don't care :P

i have a open/semi locked centre, it whines badly, has since i got the car 18months ago. what would you expect for something that has over 400,000km's

would rather but putting that $60 towards bearings for a t-series.... haha

oh and 4k/4ac's have mechanical fuel pumps that are attached to the head so there isnt one in your boot..

[Ma61Rims4Sale]

i may have been misguided by other suggestions, but could it maybe be the alignment of the tailshaft? hard to tell without much information.

[Golberg]

I had a fairly randomised knocking sound all the time in the rear end of my AE71, turned out that it was the passenger side rear shock. With the shock out I could move it up and down and feel why it did it, it was like there was a small amount of play before it started to "absorb the shock". Its not very hard to pull a shock out, and if it sounds like it may be coming from one particular side you'll know if the shock is stuffed as soon as you press down on it(whilst its out of the car).

Just thought I'd throw another idea out there

[ae71]

i have several noises in my back end, when i go into a driveway and one wheel is unloaded my spings make a "pong" noise and when my shocks reach full extrention over bumps they make a more of a "thud" noise and when my tyre touchs my guard i makes a "shreak" noise..

and then there is several whines i can pick from the diff :P

[blair]

lol.

locked diffs make so many noises

man up?

[Rob]

Hey mate, bring it to the shop one saturday and ill have a listen. Hope the lockers goin good for ya :2thumbs:

[pebbles]

<div class='quotetop'>QUOTE (slidn_ways @ May 25 2008, 01:02 AM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=536260)</div>
does this noise only happen when your turning?

it sounds like what my mates fully sic vl commodore used to do, it was complete with leb spec welded diff did, or "mini spool" as they would have you believe when purchasing from them.

what happens is, when your turning, your rear wheels are still trying to both travel the same distance, when the inside wheel has less distance to travel it skips instead.

this is why a 2 way lsd is choice, because under full load it locks and yet when turning at slow speeds it doesn't lock allowing you to turn normally.

i know you said that your diff wasn't always welded, but then again maybe your just crazy.....lol[/b]

lol,
i am well aware of the skipping and why it is there, thats not what I'm talking about haha

forgot all about this thread,

noise still there, don't really care, don't really notice

cheers for all the suggestions tho lol

edit: and yeah rob locker is going sweet, might seeya later if I'm here when u pick that diff up

to all those in adelaide who want to get there diff locked get rob to do it,
he does it quality and for cheap to!

[shelldrake]

<div class='quotetop'>QUOTE (Ma61Rims4Sale @ May 26 2008, 09:34 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=537123)</div>
i may have been misguided by other suggestions, but could it maybe be the alignment of the tailshaft? hard to tell without much information.[/b]

Tell me more about this tailshaft alignment. I have a "unbalanced" vibration that occurs inconsistantly, but always on decelleration and always at speeds above 80-90 kph... The tailshaft was balanced when I had it extended but I wondered if the t/s was skewed a little bit(In any direction. I also wondered if I extended it enough, like perhaps the vibration is the shaft wanting to pop out the back. Any thoughts on who can align my tailshaft accurately. I will try and get a measurement between the diff flange and tail of a standard car and then match that with mine tonight...

By the way, I have had a fump fump fump noise too - Turned out to be an axel bearing, often hard to tell if you havent got a direct comparison with a good bearing.

Sorry for the hi-jack.