Just been sorting a few bits out on the Trek EX8 and noticed that the rear shock is now hissing when the rear end is compressed. Do they normally do this (not noticed it before) or does it need a seal change?

It is holding its pressure and the external shaft has been cleaned, lubed and cleaned again and can't see any dirt holding the seal up.

Any ideas?

Any ideas?

Possibly a nitrogen leak, they usually make a wooshing noise when they go.

Does that mean a trip to Mojo to get it fully serviced?

Yes or TFT.
My mates RP23 hisses a bit, apparently its always done it!

Mine on my Trance has done i since the day it was new, I like to think of it as confirmation it's working hard !! 🙂