Auto Locking Hubs explanation

[wopr21]

Ok Ive gone through a lot of threads here and cannot find an answer to my question.

I have a 2001 F250 7.3 Diesel. I just replaced both auto locking hubs and wheel bearings. All tested fine and according to my mechanic, all is working normally. I want to know if 4WD low engagement is the same as getting out of your truck and locking the hubs manually. If I have my hubs in the "auto" position, why do I still have to get out and rotate the hubs into manual. Some people are telling me that because of limited slip differential that I dont have full 4WD until I get out and change the hubs to manual. So my question is why have auto locking hubs if I still have to manually change the hubs.

It seems like I have half 4WD until I lock the hubs myself. Then its great. I've gotten stuck in snow many times thinking I have engaged 4WD when I haven't.
Its frustrating when everyone with 4WD is just plowing past you.

Thx anyone

wopr21

[Term3]

Ok here's my understanding, as for 4WH or 4WL has nothing to do with the hubs that is just a gear change in the transfer case. As for the auto hubs if you are going in reverse it is possible to un-engage a wheel depending which wheel has the most traction and for driving forward is I believe the opposite. Manually locking of the hubs locks them to the axel but then unless you have a limited slip or a locking diff you are still spinning the tire that has the least traction. Like I said, this is my understanding, I could be wrong.

[whitextreme]

High and low are just in the transfer case. If you have to get out and engage the hubs manually you have a vacuum leak or the switch by the vacuum pump that controls the hubs is bad.

[jtk27]

Term 3 has a pretty good understanding. 4L and 4H is a gear change in the transfer case. Stick it in low and you'll see. The hubs auto lock but as with any open/limited slip differential the least traction is the easiest to spin and it will. Locking them in locks them both, but this is harder on your components because nothing gives. Auto-lock is fine for 90% of the situations manual lock is your maximum traction but harder on your stuff for driving distances.

[whitextreme]

Since the auto hubs only run off of one vacuum line shouldn't they be both be locked when the truck calls for 4 wheel drive if the system is working correctly? I didn't think that there was any difference between the auto and locking them if they work. Please shed some light on this if I am wrong.

[BryceB]

Originally Posted by whitextreme

Since the auto hubs only run off of one vacuum line shouldn't they be both be locked when the truck calls for 4 wheel drive if the system is working correctly? I didn't think that there was any difference between the auto and locking them if they work. Please shed some light on this if I am wrong.

Yes, both hubs lock. the dash knob is just a vacuum operated way of locking the hubs to the end of the axle and also shifts the transfer case. just locking the hubs manually does not put you in 4x4 becasue it does not shift the transfer case (the magic knob on the dash does that too). A full manual 4x4 set up, the transfer case would be shifted with a lever and the hubs would have to be manually turned.

Unless you installed a limited slip differential in your front axle, you don't have limited slip in the front, just the rear axle. AFAIK, LS was not an option or our trucks in the front axle. So forget about LS in your front.

Locking the hubs (either with the automatic vacuum method on the dash or getting out and turning the knobs) locks your wheels/hubs to the axles. the differential is still a differential. It does not lock the 2 halves of the axle together. The wheel with the least amount of traction will get the most power in an open differential type set up.

[16cat]

check your vac lines for good seal mine had dry rotted, i cut the ends off and reused them work great now

[wopr21]

Lots of great feedback on this. Thanks everyone.
I still would like to know why there is such a thing as "auto locking hubs" if I still have to get out and lock them manually. Kinda defeats the purpose of have the auto lock option.

If the system is working properly, will I see the knob on the will hub move to the manual position?



wopr21

[Term3]

Nope all internal.

[wopr21]

So I guess if I'm going to need real 4WD , I'll need to plan ahead and lock the wheels manually. True?

wopr21