So I am looking for confirmation of what I am assuming is correct from what I have read in regards to our 4x4 system.

The hubs are either in auto or lock position. In Auto the are shift on the fly and vacuum engaged hubs? Is that Correct?

In the lock position it is no difference than any other manual locking hub and does not rely on the vacuum system at all. Correct?

If you put in aftermarket manual hubs you loose the "auto" ability of the hubs?


Thanks in advance.

 

No, problem, hopefully that info helps.

 

Excellant info so far, just 1 thing that isn't apparent..

When you manually lock in the hubs (whether they are OEM shift-on-the-fly, or OEM/Manual lock type) the front half shafts And front drive shaft are turning because the front tires are "connected" to them.

Thus, you are having increased drag and can have more wear if you leave things like this for a really long time.

I have manual 4x4 (floor lever) and leave my from hubs locked since I'm mostly in the mountains with snow at the moment (CO). But, on a 2-hr highway drive I'd unlock the front hubs to avoid any problems, if I hit a pass with snow, I can get out and lock-em in again.

 

Thanks!!!!! I'm pretty familiar with most 4x4 systems and have had a couple decently built off road rigs. And have had the Chevy/GM auto transfer case. But this set up had me scratching my head with auto but still have manual locked hubs.

Glad I got it sorted out in my head now!! Now I just need to track down why I get nothing in the auto mode.

 

Dirty hubs or broken vac lines and seals are the normal culprits. The tech stickies include guzzles article on cleaning the hubs and it isn't hard. I did mine a few times until I got to where I just couldn't trust them to engage or disengage when I needed them. I constantly had to get out and try to spin the front stub axles to see if they were locked. I drove a few hundred miles with one side hung up after going back to 2wd causing a vibration and that was the last straw for me. Finally went with Mile Marker stainless manual hubs. Easy to work and I know for sure when they are engaged or not. The vac lines like to rot out going to the knuckle and finally the vac seals in the knuckle itself can leak bad enough to cause issues. New auto hubs is an option also, but they are pricey.

 

Almost anything "auto" is a source for throuble and added maintenance.
There are more than enough threads of vacuum related issues, or failure to engage/disengage that I wanted a manual (floor lever) transfer case on my F350 for plowing as well as in the donor 4x4 '05 F250 I have to swap into my 2wd Excursion.

 

I leave my hubs locked all winter or 6 months of the year, no issues. When I do replace the factory hubs I'll go with a set of Warn's.