4x4 issues - Diesel Forum

mn7.3 · 10-16-2009, 12:11 AM

i have replaced both auto locking hubs and the switch in the cab and still the hubs will not engage unless i get out and lock them in manually. when the hubs are in the lock position the switch will work to go from 2 to 4 wheel but will not work if the hubs are in the auto position. it is on a 2003 f350 any ideas would be helpfull thanks...

Tony_ONeil · 10-16-2009, 08:08 AM

You check the vac lines connected to the knuckle?
They're known to leak on these trucks and if that happens the switch will not engage the 4x4 because the hubs will not be activated. if they have to be locked manually for the switch to work I'd check there.
If they are bad I recommend checking out dieselsite.com
They have some nice replacement ones

Texascadillac42 · 10-16-2009, 10:21 AM

Could be the lines, or the seals inside the hub. If either of them has a leak, then the auto hubs wont work.

**my03psd** · 10-16-2009, 04:27 PM

I had to replace both of my front hub bearings because I was losing vaccum there.Tested w/ a smoke machine like you do EVAP on a gas car and had already replaced all seals w/ ball joint job and found them to be leaking at the bearings.