DIY – Rear Axle / Differential oil change, with pics – for FAQ
10-10-2006, 01:06 AM
#42
Melting Slicks
Thread Starter
Update added to first post of this thread... near bottom.
Member Paulct alerted me to the fact that the rear spring in his `05 model partially blocked access to the axle drain plug... unlike on my `06 model. For details, see update in post #1.
http://forums.corvetteforum.com/show....php?t=1497063
Member Paulct alerted me to the fact that the rear spring in his `05 model partially blocked access to the axle drain plug... unlike on my `06 model. For details, see update in post #1.
http://forums.corvetteforum.com/show....php?t=1497063
10-10-2006, 07:02 AM
#43
Drifting
changed mine..... 6000 miles....
used to make noise after sitting for a few hours.....
NOT ANY MORE....
thanks for the info....
2006.... 10mm (not torx).... no problems....
will probably change it one more time in about 200-500 miles (just to see what color the oil is)
used to make noise after sitting for a few hours.....
NOT ANY MORE....
thanks for the info....
2006.... 10mm (not torx).... no problems....
will probably change it one more time in about 200-500 miles (just to see what color the oil is)
10-10-2006, 07:44 AM
#45
Instructor
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Ref: Chatter in relation to build date...
My '06 was built 1/12/06 and chatters like a nudist sunbathing at the north pole. Now has 13.5K miles. Has been chattering since about 8K. Dealer is willing to do fluid change. I plan to get that done soon and will report back with results. Just for kicks, I also plan to do the figure 8's this afternoon after work and see if it helps any and, if so, how long it lasts. Don't expect any improvement, but why not try it and see for sure!
10-10-2006, 08:29 AM
#46
Le Mans Master
My '06 now has ~14K on it and I've done some auto X's with it so I am thinking of changing out the diff fluid (already did the MN6 tranny) but I am confused as to using the mineral base or synthetic fluid? So far no rear end noise so this is strictly a preventative maintenance issue. Please help me decide what fluid is best suited for my needs! 
10-10-2006, 09:29 AM
#48
Melting Slicks
Thread Starter
Originally Posted by Miaugi
...I am confused as to using the mineral base or synthetic fluid? So far no rear end noise so this is strictly a preventative maintenance issue. Please help me decide what fluid is best suited for my needs!
Don't get fooled into thinking that synthetic is "better" than mineral. GM posi rears used mineral oil since day one and have lasted very long with no problems. I know some would rather eat nails than use oil other than synthetic because they feel synthetic is far superior, but try to put that illusion behind you.
The TSB also says to use synthetic IF putting in new clutch packs, but keep in mind that, as far as we know, the "new" clutch packs are made of a different material than those installed in C6s before 12/05... and at this point may even be different than later ones too. So, it is possible that the engineers spec synthetic for the "new" replacement clutches only (due to their composition which may be more synthetic-friendly), and know that the factory clutches need mineral instead. Just theorizing... but when in doubt, follow the TSB.
Or you could just leave your differential alone until it starts scrubbing.
10-17-2006, 01:01 PM
#49
Melting Slicks
Thread Starter
Just updated the differential fluid change DIY... added the latest 10-13-06 TSB... thanks to retrorod for providing that. Figured I'd bump this thread anyway since there seems to be a lot of axle related activity today.
10-18-2006, 02:08 AM
#50
Anyone want to hear from an old fart?
GM limited slip differentials have long become noisy after some miles. I'm not sure about the solid rear axles, but independent suspension rear gear cases have long done this.
An 'additive' has been specified as long as I can remember. I'm sure the orginial fill in all Corvettes has the additive in it, it's not just for noisy clutches. Regular gear oil smells bad, and the additive just makes it worse.
(You wanta hear the story about whale oil? The 'original' additive was supposed to be made from whale oil/blubber. When whaling products were banned in the US, GM had to develop a synthetic version of this. I'm not sure about the truth of this, may just be an early 'urban legend'.)
A usual fix for the noise was driving in about 5 tight right hand circles, then about 5 tight left hand circles, or about 5 figure 8's. This was supposed to work the clutches and open the surfaces up, getting oil/additive into the clutch packs. The noise basically came from the clutches not slipping for come time and getting dried out of oil. The tight turns worked the oil back into clutches and eliminated the noise.
I don't remember what milage it started at, but my 1972 did start noise and the figure 8's quieted it right down.
Has anyone with a noisy C6 actually tried the circles/8s before a dealer oil replacement? I would like to know if the old solution will still work on the new car?
GM limited slip differentials have long become noisy after some miles. I'm not sure about the solid rear axles, but independent suspension rear gear cases have long done this.
An 'additive' has been specified as long as I can remember. I'm sure the orginial fill in all Corvettes has the additive in it, it's not just for noisy clutches. Regular gear oil smells bad, and the additive just makes it worse.
(You wanta hear the story about whale oil? The 'original' additive was supposed to be made from whale oil/blubber. When whaling products were banned in the US, GM had to develop a synthetic version of this. I'm not sure about the truth of this, may just be an early 'urban legend'.)
A usual fix for the noise was driving in about 5 tight right hand circles, then about 5 tight left hand circles, or about 5 figure 8's. This was supposed to work the clutches and open the surfaces up, getting oil/additive into the clutch packs. The noise basically came from the clutches not slipping for come time and getting dried out of oil. The tight turns worked the oil back into clutches and eliminated the noise.
I don't remember what milage it started at, but my 1972 did start noise and the figure 8's quieted it right down.
Has anyone with a noisy C6 actually tried the circles/8s before a dealer oil replacement? I would like to know if the old solution will still work on the new car?
10-22-2006, 08:40 PM
#51
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I'm researching doing this changeout myself at the next oil change, as I've had the chatter recent mornings leaving the driveway, and often driving just slow speeds.
Now, I just want to make sure I'm reading this right... regarding the new TSB (10/13/06) in post#2: are the lubricant & additive part #s the same for both "first complaint" and "repeat complaint"?
Thanks!
Now, I just want to make sure I'm reading this right... regarding the new TSB (10/13/06) in post#2: are the lubricant & additive part #s the same for both "first complaint" and "repeat complaint"?
Thanks!
10-23-2006, 12:23 AM
#52
Melting Slicks
Thread Starter
Originally Posted by caw0917
...I just want to make sure I'm reading this right... regarding the new TSB (10/13/06) in post#2: are the lubricant & additive part #s the same for both "first complaint" and "repeat complaint"?
What does not make any sense to me is why replacing the differential fluid with the same stuff that was already in there is supposed to cure the problem. It would seem, at best, to be merely a temporary cure.
At least when the non-synthetic mineral oil was being specified for use by the previous TSB, we thought that maybe the engineers had discovered that the synthetic oil ITSELF was causing a problem with the clutch packs... and it made sense to drain the synthetic and put in the mineral.
But now that they are specifying the synthetic, it either means that the oil itself had nothing to do with the problem (and thus a mere oil change is nothing more than a temporary fix), OR, they have no idea what they're doing and are just guessing, wasting everyone's time. Only time will tell at this point.
10-23-2006, 01:06 AM
#53
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Originally Posted by Vet
...they have no idea what they're doing and are just guessing, wasting everyone's time.
Think I'll hold off on replacing the clutch packs myself, though if it comes to that
(edit-addon question): where can I get my hands on some of the gm-spec lubricant/additive? Do any of the forum vendors sell this stuff, or should I just walk into a dealer and confuse the heck out of some salesperson?
Last edited by caw0917; 10-23-2006 at 01:35 AM.
10-23-2006, 01:48 AM
#54
Instructor
I had the noise on my 05 at about 4k miles. Went to the dealer to complain about it and they told me it would cost around $300 to change the fluid because it's suppose to be routine maintnance. I just left because I didn't feel like arguing with the idiot. I then went and bought 2 qts of Royal Purple 75/90 and swapped the fluid myself. I have 10k miles now and 6 months later, the noise went away and never came back after I swapped the rear fluid.
It was worth the $25 I spent on the fluid and the hour of my time to not have to drop my car off at the dealer.
It was worth the $25 I spent on the fluid and the hour of my time to not have to drop my car off at the dealer.
10-23-2006, 10:23 AM
#55
Melting Slicks
Thread Starter
Originally Posted by caw0917
where can I get my hands on some of the gm-spec lubricant/additive? Do any of the forum vendors sell this stuff, or should I just walk into a dealer and confuse the heck out of some salesperson?
Ken Fichtner
email: kenfichtner@fichtnerchevrolet.com
Gene@FredBeans
email: gculley@fredbeans.com
11-23-2006, 04:33 PM
#56
I have called several Chev dealers plus one large Cadillac dealer in the Los Angeles area. None of them has had any one come in with this rear end growl complaint so I suspect no Chev service department (or Cadillac dealer) in the Los Angeles area has performed this fluid change or clutch relpacement.
I have the noise problem on my 2006 C6 but I am going to wait.
I have the noise problem on my 2006 C6 but I am going to wait.
11-28-2006, 11:50 AM
#58
Burning Brakes
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Originally Posted by Vet
Quick update...
I changed the oil in my axle using the non-synthetic oil and additive as outlined in the TSB. Upon backing the car out of the garage right after the change, the noise was still there, but that makes sense since at that point the oil hadn't been worked into the clutches yet. I then drove the car for about 20 miles, including doing about eight figure-8s in a parking lot. Put car away.
Took the car out again a few days later... cold scrubbing noise completely gone.
I find it quite interesting that a mere oil change can have such an immediate effect on this problem.
I was planning on changing the oil one more time soon in the name of performing a true "flush".... with hopes of having the axle behave at least throughout the winter... so I don't need to crawl under the car in 20 degree weather
.
Any theories on why a mere oil change instantly kills the noise? I had thought that maybe the fresh oil cleaned varnish off the plates... but you'd think it would take a while for that to happen if that was the case, not just 20 miles and a few figure 8s.
All the more reason to do a true flush, meaning changing the oil out two or maybe even three times. Because apparently, whatever was in that axle (the old synthetic oil itself, or varnish...???) was causing or greatly contributing to the noise, thus getting as much of it out as possible would be the best thing.
I took the car out yet again yesterday... no noise.
Thoughts?
I changed the oil in my axle using the non-synthetic oil and additive as outlined in the TSB. Upon backing the car out of the garage right after the change, the noise was still there, but that makes sense since at that point the oil hadn't been worked into the clutches yet. I then drove the car for about 20 miles, including doing about eight figure-8s in a parking lot. Put car away.
Took the car out again a few days later... cold scrubbing noise completely gone.
I find it quite interesting that a mere oil change can have such an immediate effect on this problem.
I was planning on changing the oil one more time soon in the name of performing a true "flush".... with hopes of having the axle behave at least throughout the winter... so I don't need to crawl under the car in 20 degree weather
.Any theories on why a mere oil change instantly kills the noise? I had thought that maybe the fresh oil cleaned varnish off the plates... but you'd think it would take a while for that to happen if that was the case, not just 20 miles and a few figure 8s.
All the more reason to do a true flush, meaning changing the oil out two or maybe even three times. Because apparently, whatever was in that axle (the old synthetic oil itself, or varnish...???) was causing or greatly contributing to the noise, thus getting as much of it out as possible would be the best thing.
I took the car out yet again yesterday... no noise.
Thoughts?
Only thing that makes sense is that the new oil you put in has worked in and around everything in the axle by your doing the extra figure 8s.
What a pain. I think I will change the oil myself AFTER I get the car back tomorrow from my roof "fix."
Thanks for the very helpful information.
11-28-2006, 12:21 PM
#59
Melting Slicks
Thread Starter
Originally Posted by wsharp24
Isn't the latest TSB stating to use the synthetic oil rather than the mineral oil?...Thanks for the very helpful information.
Yes, synthetic is now specified for the flush per the latest TSB (10-13-06). Refer to the first three posts of this thread for the most updated info.
I will continue to keep the first few posts of this thread as updated as possible at all times. The part you quoted above must be from later in the thread, but prior to the new TSB... thus not updated.
Thanks again!
11-28-2006, 12:38 PM
#60
Burning Brakes
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Originally Posted by Vet
Thanks!
Yes, synthetic is now specified for the flush per the latest TSB (10-13-06). Refer to the first three posts of this thread for the most updated info.
I will continue to keep the first few posts of this thread as updated as possible at all times. The part you quoted above must be from later in the thread, but prior to the new TSB... thus not updated.
Thanks again!
Yes, synthetic is now specified for the flush per the latest TSB (10-13-06). Refer to the first three posts of this thread for the most updated info.
I will continue to keep the first few posts of this thread as updated as possible at all times. The part you quoted above must be from later in the thread, but prior to the new TSB... thus not updated.
Thanks again!
Darn, if I knew I was going to have this much hassle with getting warranty work done I don't think I would have bought this car. I'll change the fluid myself.
Unless the labor runs over 2 hours they want me to sit in a waiting room and wait on the lovely thingee with the rest of the girls (ladies, don't take this the wrong way). Spending this kind of money, I am not used to wating in a customer service area...hmmm, wish Lexus sold Corvettes...they sure treat you a lot better. Heck, I could have bought a used Caddilac and gotten a rental car from the get go....no 2 hour labor issue involved.
Guess this is what happens when you go back down to buy a Corvette...sorry, had to vent.
Hey, even bought the GMPP MAJOR Guard and they don't want to treat customers any better...saying they have to go by Chevy rules...last time I looked I thought GM owned Chevy. Don't want to give me a rental car.
Sorry....had to spit this out. I think I will be doing my own work on the car from now on...wish I could fix the roof without taking it in.
