Bit the bullet and got a brand new ADD unit from toyota. i managed to get it for less that the recomended retail of $635 through a mate, but it still wasnt cheap. $480 + 2 L of diff oil + gasket goo
Fits step was removing the old unit from the front off the diff housing. As i started to undo the bolts, diff oil started seeping out and i relised i would have to drain it. 2 10mm allan key bolts on the diff for the drain and refill. I also had to shoot out and get some diff oil. SR5 front diff takes 1.7L
Diff with ADD unit removed
Old ADD unit removed. I noticed that there was very little gasket material on the surface where it mounts to the diff.
Old ADD unit appart. you can see the water marks inside. The ADD unit has an electric motor which moves a series of gears which slide the arm left and right to engage/ disengage drive to the drive shaft.
Old Breather off the ADD unit. Check out the hole in where some vandal from ARB has carelessly ripped it off with a set of pliers when i got my lockers installed in March. That would be the source of the water in the ADD unit and the cause of all my problems. Thank you ARB Artarmon!
New ADD unit from the back side
New ADD unit in Place. With my shiny new breather hose! It didnt come with a gasket so i just made a new one using gasket goo
Refilling front diff oil. Patent Pending on the garden hose. The hose fitted perfectly into the filler hole and the spout of the oil container. I just had to cut a hole in the container to speed things up. Removing the front left wheel is the best way to get access to the drain and refill holes. I had to use a 10mm allen key for the drain as the large Monster Rides diff drop bracket prevented getting a socket in there.
So now I have 4x4 again! If anyone notice's their 4x4 light flashing, i suggest you check for water in the ADD unit so you dont have to do all of the above