Bubbles in transmission fluid ??

[Tonto]

Hi all. 3 speed auto. Noticed a month ago when I checked the fluid level there seemed to be some bubbles. Had the trans seviced, nothing appeared wrong.

Then just the other night, didn't upchange into 3rd for a while, but after a few minutes it did, then all was fine. However, checked the fluid when I got home; level was way above the max line, and despite being clear red, had lots of small bubbles.

Any suggestions? Is this normal - or, what's causing it ?

[krankieone]

over filled ????

[Tonto]

Wouldn't have thought so ... frothy before service, and frothy afterwards, so either overfilled both times (and the latter by a pretty reliable auto trans mob). Anyway, bit hard to tell now ... it reads WAY over the mark, but I figure that's due to the froth.
How would I tell?

[krankieone]

EFFECTS OF INCORRECT FLUID LEVEL
A low fluid level allows the pump to take in air
along with the fluid. Air in the fluid will cause fluid
pressures to be low and develop slower than normal.
If the transmission is overfilled, the gears churn the
fluid into foam. This aerates the fluid and causing
the same conditions occurring with a low level. In
either case, air bubbles cause fluid overheating, oxidation
and varnish buildup which interferes with
valve, clutch and servo operation. Foaming also
causes fluid expansion which can result in fluid overflow
from the transmission vent or fill tube. Fluid
overflow can easily be mistaken for a leak if inspection
is not careful.

Lifted from the workshop manual