Air bubbles on transmission dipstick

[capriblu]

I changed the gearbox/diff oil on my car today.  Filled with a GL4 80W90 upto and a smidge over (1mm) the upper limit on the dipstick.  This was with oil cold just after filling

Took car for run, everything OK but when I checked level hot I noticed quite a bit of aeration of the oil on the dipstick - level was still just a smidge over top limit.

I honestly can't recall whether I have ever checked oil level when hot so I may be worrying unduly.

Is this normal?   Concerned that I may have overfilled and that this is causing some aeration although I really can't believe that there is much more than 100 - 150 ml of oil above the 1.7 litre nominal - I had just under a third of a bottle left from 2 x 1 litre bottles added.

Advice please before I face the potential aggro of trying to remove a small quantity of oil.

[Neil-yaj396]

This is a feature of modern gearbox oil known as 'foaming' I think. It was recently debated at length either on here or the LMC Forum (try a search). I think it ended with a recommendation of oils suitable for older gearboxes and less prone to this phenomenon. Don't think it would be due to minor overfilling. My oil level has been a little over the max level for several years.