I bought this 2002 F-350 years ago, I only use it for plowing my 800' driveway. Last year I got stuck in some heavy snow, I noticed my drivers side front tire wasn't spinning but passenger side was, I had both hubs locked in. The guy who had the truck before me put Warn locking hubs on, maybe the hubs are getting a little old. I plan on putting new locking hubs on this year, I notice there are 2 kinds of locking hubs, auto and manual, I don't know which ones I have on my truck, is there anyway I can tell? Does it matter which kind I put on?

 

Welcome to the site.

Generally the hubs will either say Lock-Free or Lock-Auto on the hub face.
You might try disassembling the hub and cleaning and re lubing it prior to replacement.

 

My hubs say lock/free. I did some checking online to see what locking hubs the truck came with originally, it said that a 2002 F-350 Heavy Duty came with Auto locking hubs. I guess the hubs I have in there now are manual locking, I have a dial on the dashboard that I can set to 2 wheel, 4x4 high, and 4x4 low, does that mean it had auto locking hub from the factory?

 

Can I just put back in manual hubs without doing any changes to the vacuum lines?

 

You had the option of an ESOF (electronic shift on the fly) system, or, there would have been a manual lever on the floor to select transfer case select/options including lock/free hubs. With ESOF there's an electric gear motor to make the T case selections. If converted to manual hubs it wouldn't affect function. Could be the vacuum pump, hub seals, lines failed, or, they wanted a more 'on demand' hub. ESOF hubs being they need high/low vacuum to engage/disengage can sometimes require some extended drive to release. Not always a desirable condition.The ESOF 'lock' feature is more a failsafe op.

 

If you do noyhave locking deferential one tire can spin with out the other one spurning.

 

Is the 4 and 2 wheel drive switch on the dashboard still functional with manual hub? Put in the new manual hubs, I jacked my drivers side wheel off the ground to see if the hub lock would engage, had the ignition on, put my switch in 4 wheel and heard a click in my transfer case, turned the wheel in both "free" and "lock" positions but didn't see my front drive shaft turning. I turned the switch on 2 wheel and heard the click again, while turning the tire with the hub in "free" the drive shaft didn't turn, which it shouldn't, turn the hub to "lock" and the drive shaft spun, why does the drive shaft spin in 2 wheel but not in 4 wheel?