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So i had my diff fluid changed yesterday( i once in a blue heard a knock sound in the rear on hard turns) No biggie..get it changed...drive it home. No problems
I let the car sit over night and now the car makes horrible clunking noise on turns or even slight acceleration at slow speeds. It sounds terrible. Clunk, grind...bad.
I am thinking the local shop used the wrong fluids or could it be something worse?
I have a trip to make tomorrow and was contemplating doing it myself tonight since it seems pretty basic. Dextron 75w-90 is LS designation on bottle? Need some clarification on the fluid.
Thanks in advance guys
Last edited by Chibullies; Jul 30, 2016 at 07:10 PM.
I have never changed my diff fluid and don't know much about it but from being on this forum I can tell you most people say to do figure eights right after you have it changed to distribute the fluid in the diff. Maybe that is your problem.
Try figure eights first to mix the oil they installed. If the noise does not go away, buy three bottles. Jack the car up level and just drain and fill (you will not use all of the third bottle). Do the figure eights again.
Last edited by HBsurfer; Jul 30, 2016 at 09:34 PM.
I don't know what years apply, but 05's have to have the friction additive. I'm definitely no expert but this clunking sounds more like axle shafts needing tightened though.
Thanks for the help guys. They used Valvoline 75w-90 with valvoline additive. So thats already a foul
Im pretty sure its the Diff cause i had zero issues till it was changed. Now it sounds terrible on turns.
I am taking the car back first thing in the morning but i don't have too much confidence in them getting this right. Price i pay for not having the time to get this done myself..now i waste more time than had i done it myself in an hour.
I have three bottles of Mobil 1 75w-90 LS in case i still have to do this myself.
EDIT: I did the figure 8s earlier. no help
Last edited by Chibullies; Jul 31, 2016 at 12:03 AM.
Thanks for the help guys. They used Valvoline 75w-90 with valvoline additive. So thats already a foul
Im pretty sure its the Diff cause i had zero issues till it was changed. Now it sounds terrible on turns.
I am taking the car back first thing in the morning but i don't have too much confidence in them getting this right. Price i pay for not having the time to get this done myself..now i waste more time than had i done it myself in an hour. I have three bottles of Mobil 1 75w-90 LS in case i still have to do this myself.
The fluid I posted above needs no additive and is what GM specs for our cars now. Since you are having problems, I would not even consider another fluid. Many of us here have used this and we know it works.
Good luck.
While I have no doubts about the ACDelco fluid being the right one for the car, I will say I've watched and talked with others who have used Mobil 1 oils for parts other than the engine oil. It seems from experience of others that there is no problem using their products. I would guess that's due to their large research staff as well as their long association with both GM and Corvette.
The correct diff fluid is Dexron LS 75W-90......p/n 88862624. This blend incorporates the proper friction modifier & no additive is required. Notwithstanding others comments regarding Mobil 1 or other brands, you should use the specified fluid. In order to insure a proper refill, you need to drive enough to fully warm the diff; drain whatever fluid has been installed AND ALLOW THE DIFF TO DRAIN OVERNIGHT TO INSURE ALL THE OLD FLUID IS REMOVED. Then refill & drive 8-10 low speed figure 8's. The purpose of this procedure is to insure the new fluid is fully absorbed in the posi clutch packs. Once done, it's also a good idea to pull the fill plug again & add fluid if needed.
It could be something worse. By the way you describe the noise, they might have forgotten to refill. It could be there is no fluid at all.
I am a firm believer in not trying to second guess the engineering teams' recommendations regarding fluids (oil, coolant, gear oil, diff oil, brake fluid, etc). I only use the AC Delco oil shown in post #3 and the Delco Dexron specced for the M6.
The fluid I posted above needs no additive and is what GM specs for our cars now. Since you are having problems, I would not even consider another fluid. Many of us here have used this and we know it works.
Good luck.
Yea the dealerships are closed today so i had to opt for the Mobil which i heard was pretty much the same thing from guys on here.
Long story short...put it in and did a few figure 8s and nothing. Still the same problem....just maybe not as pronounced. Only happens at slow speeds also.
The vette has 99k miles on it. Could i have exposed something worse by doing a simple diff fluid change? Everything was fine prior.
Yea the dealerships are closed today so i had to opt for the Mobil which i heard was pretty much the same thing from guys on here.
Long story short...put it in and did a few figure 8s and nothing. Still the same problem....just maybe not as pronounced. Only happens at slow speeds also.
The vette has 99k miles on it. Could i have exposed something worse by doing a simple diff fluid change? Everything was fine prior.
PUT THE CORRECT LUBE IN IT as noted above by HB Surfer.
Don't go by what you "heard." " . . . pretty much the same . . . " won't cut it in this instance. Use the correct fluid. This isn't like motor oil, where nearly anything will work.
Fair enough, just that nothing is open today on a sunday and i am moving to Daytona beach from Tampa tomorrow.
Just bad timing...really dont want to have to tow it.
Scared to drive it about 2hrs like this.
I don't recall the fluid that was used but a couple of months ago, a guy on here put a top rated oil in his diff and immediately had noises that were not there before the fluid change. He drained and refilled with the GM oil and the noise went away.
GM engineers know our cars better than the internet experts (at least that is how I feel).
Last edited by HBsurfer; Jul 31, 2016 at 12:31 PM.
I wonder how pronounced everyones Diff noise is when the fluid is bad.
Mine sounded like something was stuck then released with a clunk. Replaced fluid with the corrected GM fluid and did the figure 8s and all has been quit for the last 6-7 years.
Mine sounded like something was stuck then released with a clunk. Replaced fluid with the corrected GM fluid and did the figure 8s and all has been quit for the last 6-7 years.
Yea, that sounds like mine...along with some other not so super sounds.
Little grinding here and there.
How dangerous do you guys think it is driving the car like this?
Considering i would be using the highway simply going straight..no turns. (Clunking noises only happen on slow turns)
Weighing my options until these parts departments open tomorrow
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Diff Fluid help.
You need to know...this all makes sense if the wrong fluid was put in. The DEXRON LS is the best fluid although expensive.
