I've got quaife lsd installed half a year ago. Did a few drift events and track days. When I unbolted the fill plug on the differential, strong burst of the compressed air come out of it. Does this mean the breather is stuck at some point? I suppose it's impossible to change breather tube without pulling the differential out? Any help is appreciated.

 

Probably pinched the breather line or tube

 

or the oil got extremely hot...

 

They seem to be OK

It might have gotten pretty hot on the track. Does it mean the the fluid got clogged in the breather and needs to be cleaned out?

 

No matter how hot it gets , the breather will not allow a build up in pressure.