Lahnniee

Wondering what this is. I have a P0135 code ( o2 sensor bank 1 sensor 1 ) and 2 emmisions codes.
Also what is that hole for in bottom pic? Any help would be appreciated. ( Also cruise control does NOT work ) Very new to this site hope I am in the right spot, thanks!

jordan96xj

Looks like the vent/breather hose for your front differential (helps it avoid building up too much pressure inside as it gets hot).

4.3L XJ

Agreed. It attaches to the nipple on the top of the differential housing

Lahnniee

Thanks you guys! Do I need to fix this?

BwanaBob

The hose just fits onto the nipple on the back of the differential housing
with a little hose clamp. Then you route the hose up into the engine
compartment and use a zip-tie to secure it to something that doesn't move.
Not important exactly where. The clamp may still be on the nipple from
when the hose severed. If so, just re-use it or get another clamp.

If you don't fix it, gear oil will blow out of the nipple and in time make a mess
and reduce the oil level in the diff. If the nipple is left open and you drive in
puddles, water can get in the diff and make the bearings rust.

JK253

Mine did that before as some of the zip ties broke. You can either replace the hose or probably just re-use it if you square up that worn end by cutting it cleanly. Looks like it has been dragging for a bit and lost the cap: https://images-na.ssl-images-amazon....dL._SX425_.jpg

Put a new cap on the hose and just tie it up as high as you can in the engine bay, away from the exhaust so it doesn't melt. The lower end should go into the back of the differential housing, just above the axle tube.

4.3L XJ

It isn't completely necessary, but is certainly nice to have, especially if you go through any water. You an use some new hose and route it anywhere you like up on the frame or firewall.