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Diff whine getting worse
http://classiccamaroclub.mfatw.com/viewtopic.php?f=6&t=2415		 Page 1 of 2
Author:  heinz5774 [Wed Jul 25, 2012 9:12 pm ]
Post subject:  Diff whine getting worse
Greetings all,

Hope you are all enjoying the more pleasant climate we have been blessed with lately,

My beast is a 99 Z28 manual.

I have mentioned on here before i have a diff whine that comes on at about 40, rises gradually and then fades after 80. Its not bad and i can live with it .

More recently however i have another louder whine coming on when i decelerate from about 40 and carries on till i stop, doesnt matter if the clutch is in or out, as i pull up i can feel vibration through the car.

This is in deceleration only, its quiet when pulling away.

The diff oil is Redline and new,

I am wondering if anyone has experience of delving into one of these things as i understand setup is critical.

I am also considering a friction reducing additive such as Activ8 which has had some success for some folk.

Question is will this work with this type of LSD and cause no problems, i understand this model (99) works with gears not friction

plates.

As always your input is much appreciared.

Many thanks, ben.
Author:  Z28DUNC [Thu Jul 26, 2012 9:25 am ]
Post subject:  Re: Diff whine getting worse
Hi Ben,
From my experience get the correct GM diff additive and oil. If that doesn't cure it time to take it a part as somethings shagged.

My diff was making bad noises and I put in GM oil and additive and it's been fine since, defo worth a try.

Dunc
Author:  maudyZ28 [Mon Jul 30, 2012 1:21 pm ]
Post subject:  Re: Diff whine getting worse
yeah the 99 has a zexel torsen gear type LSD or rather posi drive in this case. LSD specifically use clutches or plates...anyway, there was a common fault called the 'rusty screw noise' on these diffs. Although the additive is not required it is suppose to help the noise in the gears. Redline also do their own aditive to go with the oil. Did you check the c-clips on the end of the drive shafts for wear when you pulled the cover if you personally changed the oil, and is there any play on these, ie jack up the car and do the wheels pull in and out and knock by an excessive amount?

I think mine still makes a bit of noise but with the exhaust I cant really hear anything else....is that a better solution???? :D
Author:  heinz5774 [Thu Aug 02, 2012 3:19 pm ]
Post subject:  Re: Diff whine getting worse
Many thanks for that,

I did not do the oil change on the diff as my driveway is angled and steep and i have no garage. Also given the hours i work its more economic to work and pay someone to do the car.

The local garage does the basic stuff and they seem fair but of course are not specialists, which i would prefer but i use it on a daily basis.

I used the same Redline mix as yourself using one bottle of straight and one with additive. The high speed whine has reduced a lot which is great but its the low speed one coupled with the vibration that worries me.

The car has about 70k on it and i dont think the c clips are worn as the noise remains the same with direction changes. However i asked the mechanic to change the wheel bearings last time it was in and he couldnt without trashing the clips so he said . So as the bearings were fine anyway it was left alone till i could obtain some new clips. So i would hope any wear would have been reported.

I do agree about a louder pipe and thats definately on the list, straight after getting the wipers to behave and the damn ABS light coming on.

Many thanks, Ben.
Author:  maudyZ28 [Wed Aug 08, 2012 8:13 am ]
Post subject:  Re: Diff whine getting worse
hahah the dreded ABS ligh lol, only joking. Mine comes on all the time. Either faulty sensor or sensor ring is dirty? Does your model have traction control.

Ok, well I dont know how the guy is TRASHING the c-clips though . Whatever you do, YOU DO NOT force the drive shafts out (which is the only way I could see to trash the c clips)

The process:
Remove wheels and brake calipers and discs
Diff cover off
Remove 8mm bolt holding the diff centre block in place (hard sometimes)
Push the driveshaft in (will move only 5mm or so) c-clip will drop out into the diff centre (try catch it) - repeat with both sides
The drive shafts will now pull out easily

3 bearings to replace - one much easier than others

1) Bearing at wheel end, pull axle seeal and bearing and replace
2) DIff bearing, remove the diff unit and pull out (bit of force required), remember where diff spacers went - pull bearings off ,1 either side) and press new ones on, usually need a press
3) HARDEST ONE, pinion bearing - wont go into it as if they are doing this they should be ale to set diffs up etc, need marking paste and new pinion bearings and crush rings.......

Hope this helps. I may have a whine in mine and some are naturally noisy but it's not deteimental

I know a guy on here who's c-clips went on a LOW milage car, GM installed some of the diffs too tight.

Oh, and youll have trouble getting c clips, i gave 2 away (silly move) as I had to buy replacements that were wrong and my father, an engineer has to trim them down - yet to test them :S
Author:  heinz5774 [Thu Aug 09, 2012 2:46 pm ]
Post subject:  Re: Diff whine getting worse
Hi there,

I agree with you that the clips should not have to be damaged and i am very wary of the necessity of such a move. the chap says the shafts will not move enough even with sensors removed and something else removed to get the clips off.

Now im pig in the middle here i cant talk about something i havent seen though i am mechanical i just dont have the time or facilities.

The guy who works on it is no idiot and is used to a variety of cars, he drag races big vintage v8s and even had the chap from the local American specialist down for a look, and hes got years of experience so im not thinking incompetence here.

When i bought the car the seller said hed done the wheel brgs, is it possible he did anything wrong that could cause this? im clutching at straws but running out of ideas.

I wasnt planning on messing with bearings in the diff though i dont think id trust them to do it with that level of expertise required.
But of course im paranoid now, thanks for that, Ha.

.
As for the ABS light , i had the sensors cleaned and it has the traction cntrl. It comes on usually after about 5 miles or so, and always with the handbrake and ASR light, but it can stay out for 100 miles or so.
OR and heres where it gets interesting it will come on straight away if the cars been in the sun all day. it certainly seems temp sensitive.
It can go out sometimes if i stop and restart.
Was a ballache at this years MOT as the car was hot when i took it in. Failed it.
Eventually grudgingly passed it when it was put in next morning cold.

Maybe its the abs box but i aint spending 1200 dollars on new, thought about ebay but it wont bother me til next MOT time.

Ill keep digging about these clips, i really dont want to mess with them, may have to try another mechanic .

Many thanks as always, ben.
Author:  chevy-stu [Thu Aug 09, 2012 6:26 pm ]
Post subject:  Re: Diff whine getting worse
Have you checked the toothed ABS reluctor rings on the hubs in case they are broken or blocked causing intermittent readings.

Had this on my Mitsubishi, took ages to find.. new rings solved the problem..
Author:  maudyZ28 [Fri Aug 10, 2012 9:46 am ]
Post subject:  Re: Diff whine getting worse
mine does it after goiung over un even ground, I have efilive so free to clear codes etc...if its a V8.... where are you based?

Maybe the wheel bearing were done incorrect but f it was a while ago you would have noticed? If oil doesnt get to them they may get noisy.

if he has done these cars he should be able to figure it, seriously its as I put , diff cover off, centre fixing block out, stuff off shaft hubs and push shaft in and c clip literally falls out....
Author:  z28stu [Fri Aug 10, 2012 11:39 pm ]
Post subject:  Re: Diff whine getting worse
Hi guys
lots of talk about c clips just thought id share my personal experience with them
I had to change the rear w/bearings on my 1999 ls1 auto
Time limit was 4hrs to fit new bearings as i had to get it out the workshop ready for work start on monday morning
I purchased new bearings and new c clips from usautomotive as maudy has already stated diff cover off caliper etc the c clips fell out then pulled out shafts easy
New c clips from usautomotive were massive nearly twice as tall as the ones i took out from my axle no probs use the original ones !!!
I purchased the last chance wheel bearings just ment it runs on a different part of the axle shaft saves you buying new shafts if the old bearings had worn a groove in the shaft
fitted new bearings put axle shafts back in to find i coudnt fit my original c clips not enough of a gap to pop them back in so
shafts back out checked every thing again back in still couldnt get the clips in. Times now ticking and running out of options
In the end i had to grind down the thickness of both c clips to get them to slide easily onto the shafts center block back in drove out the work shop which pleased my boss
I phoned usautomotive regarding why i couldnt fit my original c clips he made a phonecall an came back with what your supposed to do is get the shafts lathed at the end were the flange starts to allow the shafts to go in further to get yer correct thickness c clips to slide in
He also had to order original c clips from gm/usa so i sat tight waited for original/genuine clips to arrive
shafts back out etc ground down shafts not by much until shafts went in far enough to get clips in easily

Just wondering Ben if the guy who fitted the bearings before you bought the car fitted the last chance wheel bearings but didnt grind the end of the shaft (flange end) or shaved the c clips enough and has forced the c clips into place
which inturn means they now wont come out


Hope it makes sense
Cheers Stu
Author:  maudyZ28 [Mon Aug 13, 2012 12:49 pm ]
Post subject:  Re: Diff whine getting worse
ah ha, i wasnt aware of these types of bearing but could be a possiblity...
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