Car Dumped Diff Oil after Recent Rear Diff Bush Replacement

Hi All,

Car is a 2010 Falcon FG (XT). Two weeks back had the rear diff bushes replaced as they were worn. Fast forward this weekend, heard a weird sound when driving but didn't notice anything obvious. Luckily was only a few hundred metres away. Parked overnight and by next morning the car had leaked a ton of diff oil in the garage. Car has been towed to the mechanic. Waiting for his diagnosis.

From a layman point of view, it seems like something went wrong with the recent diff service. Is there something about a diff service that could've caused such a failure? I just want to be armed with info before I go to the mechanic.

Comments

  • Yep, because rear diff bushes hold all the oil inside the diff housing.

    • Ah ok. Thanks for that.

      I watched some diff bush replacement videos but no one talked about the oil. So wasn't sure.

      • +2

        It really depends. It's not really likely that replacing diff mounting bushes would cause an oil leak.

        From memory, there is a rubber mount on the rear cover and they may have removed the rear cover to replace the mount (bolt broke off/seized in).

        Or they may have had the whole rear diff out and damaged an output seal putting the axles back in.

        Can you see where the leak is from? The back cover, the output or input shaft seals?

  • +2

    Probably didn't reinstall a driveshaft properly, and it popped out.

  • You don't need to analyse this too much. They 100% screwed up either the bush replacement or diff re-assembly.
    Repair it is on them
    EDIT: Also never use these clowns again in the future. Diff is bog simple.If they stuff this up, they are hopeless

    • Indie dude. Has been honest and good in the past. I thought I had finally found my version of the one. :-(

    • +1

      Diff is bog simple

      How many irs falcon diff bushes have you done?

      • Replacing the diff bushes is bread and butter to a mechanic as it is a known weakness. If they cannot do it, they can't be too good.
        Personally I dont work on any cars any more other than servicing my wife's but I have repaired or replaced pretty much every part of the classic models I used to work on including plenty of stubborn bushes.
        Are you suggesting IRS Falcon diffs are more complex than usual and it is therefore 'understandable' that the mechanic stuffed it?

        • +2

          If they cannot do it, they can't be too good

          Anyone can make a mistake. They may have done 100 with no issues.

          classic models I used to work on including plenty of stubborn bushes.

          Bit different to irs falcon, have to drop the entire rear subframe, then remove axles, then remove diff, then do bushes.

          Are you suggesting IRS Falcon diffs are more complex than usual

          They are more complex than the live axles you'd be thinking of. No matter the difficulty, anyone can make an error. Hopefully they handle it properly and sort it asap for op.

          • @brendanm: Yep, that's all I am waiting to see - how he handles it.

            • @randombrick: Have they told you what the issue is yet? Should have been a priority for them today.

          • +1

            @brendanm: I watched a YouTube on this procedure out of curiosity from this discussion and it didn't seem that complex. I would 100% have a crack at it if I cared enough about the vehicle (not likely these days) but It should be a basic job to a working mechanic because it is a common fault from a very popular vehicle and they crap out all the time.
            Yes, I agree that anyone can make an error. It's how they handle it that counts. So I hope for a good resolution

            • @King Tightarse:

              Yes, I agree that anyone can make an error.

              Then perhaps the statement

              If they cannot do it, they can't be too good

              Was a bit much.

              I watched a YouTube on this procedure out of curiosity from this discussion and it didn't seem that complex.

              I've watched YouTube videos of creating various chemical compounds, and they look easy to do as well. At the end of the day, no it's not rocket science, but shit happens.

              • @brendanm: Yes, but unlike watching videos about something that I have never done, such as comparing chemicals and having some vague understanding as followed along, it seemed close to many procedures I have done before and would expect to complete it properly

                • @King Tightarse:

                  Yes, but unlike watching videos about something that I have never done, such as comparing chemicals and having some vague understanding as followed along

                  I made plenty of chemical compounds in year 11 and 12, thankyou for your concern though.

                  and would expect to complete it properly

                  Everyone would expect to complete it properly. All it takes is a weak circlip to pop a driveshaft out sometimes.

                  • @brendanm: Yes a weak circlip makes sense
                    "I made plenty of chemical compounds in year 11 and 12, thankyou for your concern though". lol

            • +3

              @King Tightarse:

              I watched a YouTube…

              If I had a dollar for every peanut I deal with in a day that could do my job because they “watched a YouTube…” and then telling me how simple it is…

  • just a guess and unlikely however stranger things have happened, they could have overstressed the diff housing getting the bushes out and in and caused the diff housing to crack.
    To clean up that mess just use degreaser and hose it away preferably towards grass or dirt ground, it will get rid of the slick of oil, however there will still be a stain as some of the oil soaks into the concreate and you will never get it out.

  • I have been told that it is a crack in the housing and he can't see what they could've done to cause it. I am to cover second hand parts and he will cover all labour. :-(

    • I wouldn't be happy with that, if it wasn't leaking before it when in, Then he is at fault , obviously damaged during the process….Simple…..

    • That's pretty crap. For the price of a second hand Ford diff he should just eat it. I can't see how a standard xt falcon would break a diff case. Also not sure how they would possibly break the case replacing the bushes either, as they are in the subframe, not the diff case.

  • Dumped may be a slight exaggeration.
    They most probably filled it a tad too much, and it has simply "dumped" its excess.

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