Auto 4x4 not working

[kb69co]

I live in Utah and during a recent snow storm I put my truck into 4 high while pulling into my driveway which has an incline. It seemed like the 4x4 wasn't working so I asked my wife to watch and see if the front wheels were turning. They weren't.
The 4x4 didn't engage until I locked the hubs from AUTO to LOCK position. Is this a hub problem not engaging in the AUTO mode or is there a vacuum problem or something else that will make the hubs not engage until put into LOCK position? The hubs are tight and have no movement in them and so I don't want to replace them if it's not the problem but I don't know how the AUTO works on these, if ran from vacuum or what.

[jesilvas]

Vacuum.
I bet your air only blew on defrost when you tried to auto lock them.
Check the lines going to the hubs.

[SniperFolf]

Agreed with the last post go down below and see it the vaccum lines are worn or tore up.. and see if they have suction.

[kb69co]

Thanks guys. I was thinking it was probably vacuum but I wasn't sure if that was how these hubs engaged or not.

[01lariat4x4]

What did u come up with? I am having the same problem.

[kb69co]

I checked all vacuum lines and nothing looks rotted of unhooked. I am waiting for some time off work next week to put a dial on it and check the vacuum on the truck side and then a hand pump on the hubs to see if there is a leak on the hubs. I called and talked to a parts guy at the local Ford dealer and he said there is a seal that runs about $70 (can't remember what he called it) that holds the vacuum seal for the hubs. He said the hubs don't come with the seal you have to buy it seperate. He said they have alot of people who replace their hubs and not the seal and then their 4wheel won't work after the replace when it did before. Any one have any incite on this.
Also I was wondering if I replace my hubs because I have no idea how old they are and I am installing new rotors, calipers and shoes next week and don't want to tear up my new rotors. I looked at the Timken ones at Auto zone but the Ford parts guy (and yes I know he is wantong to sell me theirs) said they aren't made the same as the Ford ones and won't hold up. He said they have ballbearings in them instead of a cone something that Ford uses. Didn't Timken initialy help Ford design them? anyone know if the Timken ones are alright? They are half the cost of the Ford ones and do I really need these other seals when I replace them? My truck has 200,000 miles and I don't know how long the hubs have been on it so I was thinking of just doing them while I have it all apart.

[ttyR2]

Check Welcome to guzzle's 4x4 Autolock Hub Lubrication Maintenance Web Page

[wannapowerstroke]

Yes, keep me informed. Just bought an 02 Lariat 4x4. Found Temkin hubs at autozone. I am going with them. Temkin been around a long time with quality and come with 3 yr warranty. Harley-Davidson uses Temkin in their cases for years and my techs swore by them. I'm doing my hubs this weekend. Very happy to see vacuum procedure as I have the same problem.

Good luck. Keep us posted.