I had my oil changed about a week ago on my 2016 Forester with ~45K miles. The tech toped off all the fluids and all that and said that the rear differential was leaking and that I should get it into a shop sooner rather than later. I haven't been underneath, but there doesn't seem to be any evidence of a leak on my driveway. Similarly, no weird noises or anything. Could the tech have been mistaken? Is this a better-safe-than-sorry kind of thing where i should bring it in anyway?

Not sure if this would be relevant or not, but ~5,000 miles ago, the car was hit from the back driver side while parked. The damage was mostly cosmetic with the exception of rear suspension and exhaust.

Any thoughts, wisdom or insight would be greatly appreciated.


  • Some photos would help.
    – Solar Mike
    Commented Oct 3, 2021 at 17:56
  • @SolarMike - I'll see if I can get under there but for various reasons, it's not a super-easy thing to do. i'm assuming they wiped it down and everything when they had it up on the lift. so would it be safe to assume that if there is buildup on there now that it is in fact leaking? And if so, is that enough of a leak to warrant a trip to the mechanic or can it be controlled by topping it off with every oil change?
    – Daveh0
    Commented Oct 3, 2021 at 18:14
  • 2
    It's important to know where it is leaking from and even if there are no drops on the ground under it, there may be evidence on the axle itself. Usually the leaks are around the cover and a new gasket may solve it. It can also leak out the ends of the axle into the wheels. That's a bit more work to change the axle seals. It could also be leaking around the drain or fill plug or even around the input shaft. But without photos it's just guessing.
    – jwh20
    Commented Oct 3, 2021 at 18:59
  • even if there are no drops on the ground under it, there may be evidence on the axle itself - gotcha. That pretty much answers my question of whether or not it warrants a trip to the mechanic. Thanks!
    – Daveh0
    Commented Oct 3, 2021 at 19:54
  • 1
    Ask the mechanic if he actually saw evidence of a leak or was he basing it on the fluid level being low. It is possible that it was serviced after the accident and not refilled to the correct level.
    – mikes
    Commented Oct 3, 2021 at 22:05


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