Usually found on Nissan Patrols.
This type of front hub gives you the option of LOCK or having it in AUTO.
If run in AUTO, the hubs run free.
- To engage, you have to STOP, engage 4wd in the transfer box and as you drive off they go into the lock position.
- Once in the lock position they remain there until you deselect 4wd and reverse back.
- The action of reversing back puts the hubs back into the FREE position.
- If you don’t reverse back they stay in lock which means you can now engage 4wd on the fly.
So, the Reversing Back Thing.
If they are set in AUTO and you’re in 4wd and you want to reverse there is a strong possibility that the hubs may go FREE. Not good. Especially if you’re in the sticky stuff.
- In my mind, if you’re using 4wd a lot, is to run them locked. Get the wheel spanner out and change the position. Line up the relevant arrows (see above photos).
- If you run the AUTO. Read FREE. You must lock them from time to time to get adequate lubrication of the front axle.
Why have this option? I don’t know. Is it a gimmick? I think so. Only advantage of auto/free is to use a bit less fuel and less tyre drag at high cruising speeds. Autobahns. Then again, as a wise man once told me, if you’re dragging along a three ton Nissan Patrol are you really interested in fuel economy:-)?
Reminder about FWHs and what they Do /Don't Do...First, let me dispel a few myths;
- They do not engage 4wd - this is done in the transfer case.
- They do not lock the front differential.