Just asking for a bit of advice. I decided to change the rear diff oil today having no record of it ever having been done. Struggle to get the filler plug loose, eventually did and immediately oil poured (not trickled) out.
I captured the oil, did the necessary refilling etc (got about 800ml back in before it started oozing out the filler port) and closed up.
My measuring jug (photo, no idea why it rotated) records about 1250ml came out of the rear diff; the book says 800ml and my service manual says 800ml.
Questions - how could previous/factory have got so much over in? Would it have caused any conceivable issue?
Are you sure it's all oil? If some water got in, it (and air) would be whipped into an emulsion that occupied more volume than the volume of the oil + water components alone.
@eagleeye and rasterman; I haven't used it through water (only owned it a couple of months. It's got about 76k miles on it and began life on a farm, no idea what use it may have undergone. What came out looks like old oil but may have some emulsified water mixed in. I didn't think of that.
does this one have a rubber vent cap on top? someone may have used that as the actual filler hole which is lower.
I guess condensation could also get in if there is no rubber cap or it is loose.
there was a recent thread about hooking a tube to that filler hole to protect the diff from getting any water it on a boat ramp. =running the tube up in the body higher then the high water mark.
was the gear oil in the plastic cup is warm/ hot at picture taking time?
. based on its original viscosity type and/or used condition, such may have expanded with heating.
vs. the gear oil that you put in that was cold from the jug.
@eagleeye - I'll check tomorrow for rubber vent cap. The diff wasn't warm, mildly so if at all. Whether thermal expansion would realise 50%volume increase...? Not sure about that.
I just measured it to find out how much had come out, bit surprised when I took the filler plug off and so much poured out I thought it looked odd, so measured what I'd collected in my drip tray.
You didn't confuse the front with the rear by chance?! >
That's a lot. Judging by the color, I'd say it is just gear oil. When you get water mixed in, it usually looks like kahlua/milky.
If the car wasn't level, you could probably fit that much extra in. The diff vent is tough to get to, so I'd be surprised if that was used to fill. Also, it would fill better if the plug was open (so air can escape), so it would have overflowed and been done at the right level.
Confused about which diff? No, it's the rear diff. I should know, it's my fifth Subi (2 Imprezas, 3 OBs).
I doubt filling it on anything but a severe slant to the left would allow almost 50% extra over the book capacity to be put in. I agree filling via the breather plug would be hard. I felt it's cap which seems undisturbed so I'm going with the theory that the diff was probably swamped resulting in water getting in. I don't expect the factory have means of putting in this quantity from the get-go?
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