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Thread: Advice tracking down a differential leak.

  1. #1
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    Advice tracking down a differential leak.

    I have been finding a fair amount of fluid buildup on the bottom of the cover for the front axle differential on the passenger side on my rs6. I know that leaks are common at the seal for the flanged shaft but the area around the flanged shaft is completely dry. Has anyone come across leakage from the axle differential cover. On etka, I do not see a gasket there but there is an oring on the inside. It is not coming from the prop shaft as I had replaced the seal a few months ago and it has remained dry in that location.

  2. #2
    Registered User hahnmgh63's Avatar
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    I have not had any seepage up there but as you mentioned I know of some flange leaks, although mostly on the rear Diff or at the tailshaft for the transmission (5HP). Maybe use some Brake cleaner and clean it up real well and then drive it for a day and see where it starts from. Was the fluid level very low?
    2003 White RS6 2013 Midnight Blue S5
    2013 Daytona RS5 2x944 Turbo's 1974 911 w/'91 3.6ltr motor
    Roy, WA

  3. #3
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    I have not tried to check the level yet. As you know, there is no drain plug and just a fill plug for the front diff that looks not easy to get to without taking the wheel off and possibly some other items. I did clean the area up and will check it again.

  4. #4
    Registered User hahnmgh63's Avatar
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    Definitely have to take the wheel off to get to the fill plug. I use one of those MityVac vacuum suction tools to get the fluid out. Probably about time to do mine again.
    2003 White RS6 2013 Midnight Blue S5
    2013 Daytona RS5 2x944 Turbo's 1974 911 w/'91 3.6ltr motor
    Roy, WA

  5. #5
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    Cleaning the area up and looking more closely, I think it is coming from my rear main seal. Any need to deal with it if small leak.

  6. #6
    Registered User hahnmgh63's Avatar
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    Probably want to hold off a little while depending on how bad the leak is if it's the rear main seal. Obviously it requires a transmission pull to get at. Just keep an eye on your oil level. I installed an aftermarket Timken seal on mine 10 years ago as Audi only sells the hole Aluminum flange cover with the seal in it. Not a lot of miles on mine in the last few years but so far so good.
    2003 White RS6 2013 Midnight Blue S5
    2013 Daytona RS5 2x944 Turbo's 1974 911 w/'91 3.6ltr motor
    Roy, WA

  7. #7
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    I talked to my Indy about rear main seal replacement and they say it requires the engine out to do. Is that needed?

  8. #8
    Registered User hahnmgh63's Avatar
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    Yes if it's an Auto, if it's a 6spd you can probaby pull just the transmission. Sorry, my post above was a little misleading when I just said a transmission pull. With the Auto you have to take them out as a package before you can split them.
    Last edited by hahnmgh63; July 13th, 2023 at 05:27.
    2003 White RS6 2013 Midnight Blue S5
    2013 Daytona RS5 2x944 Turbo's 1974 911 w/'91 3.6ltr motor
    Roy, WA

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