Jeep provides breather hose for axles and transfer case but they neglected to put one on the Mercedes 6 speed manual transmission that came on the 2005 and 2006 TJ's. As long as you do not do deep water crossing your should be ok. If you do play in the water I would advise to remove the plastic breather cap and replace it with a hose. The cap can be found on the base of the shifter column on the front driver side. My TJ has had its fare share of water/mud wheeling and because I did not know about the cap It has had plenty of water in the transmission. I discovered this after I dropped the transmission to replace the clutch.