I'm not sure, but I think my C4 may be overserviced. I've never added fluid to it, but whenever I check it, it's always foamed halfway up the dipstick. When I check it with the motor off (yes, I know it's supposed to be idling) it reads full with no foam. I don't have any problems with the tranny, other than the hotter it gets, the later it shifts. Could this be related? I plan on changing my speedometer gear this weekend, and thought I'd adjust the vacuum modulator for earlier shifts...

C4 fluid level question