anyone know of ill effects caused by overfilling diff fluid? i'd been getting oil in the engine bay in a very odd place and finally figured out it was my diff breather hose spilling this oil everywhere. opened the fill plug on my front diff and i'm glad i had my tray nearby. over 2l came out after all was said and done. refilled it properly, but worried there might be some sort of other damage. cv seals look ok and the primary diff seal seems ok as well. how in the hell is that even possible???? did they fill from the breather line??? shocked, amazed, and worried all at the same time.

What colour was the oil?
Other than spitting out of the breather line it shouldn't have caused any long-term damage. I would consider flushing the breather line so it can function as intended.

They probably took out the filling plug, then got distracted, came back to it and filled it up without draining the original oil ?
Mike. G reg 2.5VM Vogue Portofino red 1991- 1999
V reg 2.5td P38 Rioja red 1999- 2006
53 reg td6 Vogue Oslo blue 2006- 2015
11 reg 4.4 TdV8 Vogue SE. Baltic blue 2015- date.
https://www.fullfatrr.com/forum/topic56162...tty+affair

The diff probably appreciated decent lubrication.

The fill plug is also the level plug IIRC

They have probably adopted the level fill method to the plug (i havent tried to see how much it will actually hold). This isn't correct and instead the diffs take specified quantities.

Most likely to have clogged the breather. Longer term the aeration of the oil by the diff workings can lead to premature wear through reduced lubrication. 2015 Range Rover Autobiography 4.4 SDV8

From the L322 pages on Topix
"The fluid filler plug is not a fluid level plug.

If a thread of fluid runs/drips from the filler plug hole
after refilling, the differential has been overfilled. Drain the
fluid and refill with the correct amount.

Fill the front differential case with the correct amount of
fluid.
If the differential has been replaced, fill with 800
ml (1.7 US pints) of fluid.
If the differential has been drained but not
replaced, add 750 ml (1.6 US pints) of fluid. "

I can't see how they managed to get 2 litres in though!

Phoenix, I reckon the vehicle may have been jacked up. 2015 Range Rover Autobiography 4.4 SDV8

I was wondering if it'd drawn any water in (hence asking about the colour), used to get that on the old Defenders if the breathers had been blocked or re-routed to create a 'U' bend, which would effectively block the breather, causing a hot diff suddenly quenched by cold water, to draw in water past the seals...

Appreciate the input!
The color was black. No sign of water intrusion but smelled pretty old. Interesting part was that when I pulled the fill plug, nearly a full liter came out. Specification is .75l and I got that much out before even removing the drain plug. My only guess is they removed the breather hose and filled from there. Did the rear today and it was a normal drain and refill without drama. Just really odd how much came out of the front. Glad to hear ill effects are unlikely.
Thanks again all!