Several years ago when I changed my front diff fluid I was pretty sure I over filled and it vented some fluid and pretty much clogged the prefilter on my BAHF. 

 Today while changing my ac compressor I could see that it has vented again. It has been near 4 years since I changed it. What would make it vent fluid now?  I have a trail down the inner fender well. 

Expansion of the fluid. Might want to pull the plug and check your fluid level and fluid color. It could be foaming up on you too.

Tomorrows job since the t storm got me after compressor replacement. Just seemed strange out of the blue like that.