penick000

Pretty simple, I've got a 05, 250 diesel superduty, fx4 that won't go into 4x4 automatically. To get it into 4x4 I need to manually lock the hubs in. I noticed this right after having ball joints replaced. I am assuming it is a coincidence but figured i'd include the info anyway. Truck has 90k on it. Where should I start?

Thanks

pen

conman365

Well, you have to have your hubs locked in to use 4x4. lol

penick000

Well, i'd kind of like to let it work automatically as it should.

I'm suspect of the vacuum pump or the switch. Just curious if anyone had any advice or if there was something that commonly fails that I could check into first.

pen

2Tight

I always like to work backwards. The pump and switch were working before the recent work, right? There's nothing in a balljoint job that would effect them. If the ball joints were replaced they would have to disconnect the vac lines at the hubs. Unless the vac leak is at the other end but I doubt that is the case though. More than likely they forgot to reconnect them or that new large yellow o-ring seal they absolutely have to install is leaking and preventing the hub from sealing. I did ball joints on my SD last year and there's lots that can be wrong with those seals.

penick000

I checked the vac lines already. Didn't know about the seal you are talking about. Now we are on to something.

Thanks.

pen

conman365

Ha. Oh. I thought you meant you had manual lock outs, bc 05 superdutys came with them.