Extremely new to the concept of locking hubs

[Ewhitaker0020]

My truck is an 84 K10 with an automatic transmission.

I'm very new to the concept of 4wd hubs. I've attached a picture of my front hubs. How do my hubs work? Do they just work when I put my truck into 4wd? Are they always engaged? Do I have to back up to get the 4wd to engage after shifting the lever?

Also can somebody explain to me why I would possibly want to change over to manual hubs? Would there be a noticable improvement in mpg? The best part of a 4wd in my opinion is not having to get out of the truck in the snow and mud to lock in my hubs.

Oh and new not knew. Can't change the title lol

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[bucket]

Those are the factory optional auto-locking hubs. They are great when they work. They automatically lock in when you shift into 4 wheel drive. When you shift into 2wd, you must back up for them to unlock. I think the owners manual says 10 feet in reverse, but my two trucks that had them only had to reverse a few inches for them to unlock.

Manual hubs are more reliable and they are stronger, so that's the benefit of them.

 

[shiftpro]

Driving with locked hubs also wears out front tires faster.
Maybe a change of mindset would be the course to follow.
1. If you want 4x2/4x4 selection from the drivers seat maybe an all wheel drive SUV would suite you better.
2. You don't wait until you're stuck to get out and lock the hubs or even engage 4 wheel drive. See what you're getting into then make choices.
3. Everything Bucket said.
The first real snowfall happened the other day and now my hubs are in and won't get unlocked until spring, basically.

 

[Ewhitaker0020]

Driving with locked hubs also wears out front tires faster.
Maybe a change of mindset would be the course to follow.
1. If you want 4x2/4x4 selection from the drivers seat maybe an all wheel drive SUV would suite you better.
2. You don't wait until you're stuck to get out and lock the hubs or even engage 4 wheel drive. See what you're getting into then make choices.
3. Everything Bucket said.
The first real snowfall happened the other day and now my hubs are in and won't get unlocked until spring, basically.

If they're auto locking like bucket said then am I driving with locked hubs when I'm in 2wd? No thanks on the SUV. I have a pick up for reason. It would be hard to haul sand or gravel in an SUV.

So basically during the winter you have hour hubs locked in because you might need your 4wd at any time. But in the summer you unlock them to decrease on wear?

 

[Ewhitaker0020]

Those are the factory optional auto-locking hubs. They are great when they work. They automatically lock in when you shift into 4 wheel drive. When you shift into 2wd, you must back up for them to unlock. I think the owners manual says 10 feet in reverse, but my two trucks that had them only had to reverse a few inches for them to unlock.

Manual hubs are more reliable and they are stronger, so that's the benefit of them.

What about manual hubs are more reliable? I've never had any trouble with shifting into 4wd. And like you, I've never really had to reverse to unlock them. I'm not arguing, just learning.

Since mine are auto locking hubs does that mean when I'm in 2wd they're unlocked just like a manual hub would be?

 

[rpcraft]

FWIW I suspect that the reason the "Auto" hubs start to not engage or stay engaged after being taken out of 4wd is generally due to a lack of service or when doing service people fill the assembly with bearing grease instead of using a slight amount of grease combined with gear oil. Using too much grease causes it to compact in spots that makes it hard for the internals to shift around and synchronise while trying to lock or unlock. Also as others mentioned they are inherently weaker because a lot of the mechanism is made of plastic. If you swap to manual hubs you will have the ultimate ability to control if your front axle stubs are engaged or not and you can actually shift in and out of 4wd on the without getting out and doing anything but it will affect parts wear and handling in the long run.

You might turn it into one of those exercises where if you know you are going to be doing winter driving in ice, snow, or slick surfaces that you leave the hubs engaged and shift the transfer case selector only as needed, but when the weather goes back to normal you unlock the hubs.

I used to do that all the time in my old 1977 Jimmy after I installed locking hubs and the part time kit in the old NP203 and to be honest the gas mileage was about as crappy either way, but that was probably more about the tire size and gearing I had back then, along with the severe inability to change out more advanced items like differential gears. The one thing that was nice about it was having the ability to go to 4 Lock just by stopping and shifting the trans to Nuetral if I had the hubs locked.

 

[bucket]

Yeah, with properly working auto hubs, they are 100% unlocked when running around in 2wd.

Auto hubs can be finicky. Most of them that I've dealt with would often not engage, leaving you stuck in the snow. I did have one truck where they always worked fine though.

I always used the same method as Shiftpro when it comes to manual hubs, lock them in the late fall and unlock them in the spring. If I was going to be driving on the interstate for longer than an hour or so, I'd unlock them then too, mostly to save wear on the front proofed shaft.

 

[bigcountry78]

What about manual hubs are more reliable? I've never had any trouble with shifting into 4wd. And like you, I've never really had to reverse to unlock them. I'm not arguing, just learning.

Since mine are auto locking hubs does that mean when I'm in 2wd they're unlocked just like a manual hub would be?

Manual hubs are mechanical, controlled by you. Auto hubs have more moving parts, more parts equal more potential problems. But for most general use, with a stock tire size you would probably not have any issues as long as you keep them properly maintained. As far as leaving manual hubs locked in, that’s not really any different than what newer trucks do anyway. The front axle of all new trucks is always turning because the hubs are essentially always “locked”. The front differential just doesn’t get driven until the transfer case is engaged.
If it was me, I would keep the auto hubs until they began to malfunction. At that point I’d go to manual hubs. But as they say, if it ain’t broke, don’t fix it.

 

[gmbellew]

I have auto hubs on the 1990 suburban. I always put it in 4wd every month and drive around the farm for a while to lube and exercise the hub and then unlock them. I think regularly locking them helps with keeping them maintained.

 

[TubeTruck]

Drive slugs

 

[Ewhitaker0020]

FWIW I suspect that the reason the "Auto" hubs start to not engage or stay engaged after being taken out of 4wd is generally due to a lack of service or when doing service people fill the assembly with bearing grease instead of using a slight amount of grease combined with gear oil. Using too much grease causes it to compact in spots that makes it hard for the internals to shift around and synchronise while trying to lock or unlock. Also as others mentioned they are inherently weaker because a lot of the mechanism is made of plastic. If you swap to manual hubs you will have the ultimate ability to control if your front axle stubs are engaged or not and you can actually shift in and out of 4wd on the without getting out and doing anything but it will affect parts wear and handling in the long run.

You might turn it into one of those exercises where if you know you are going to be doing winter driving in ice, snow, or slick surfaces that you leave the hubs engaged and shift the transfer case selector only as needed, but when the weather goes back to normal you unlock the hubs.

I used to do that all the time in my old 1977 Jimmy after I installed locking hubs and the part time kit in the old NP203 and to be honest the gas mileage was about as crappy either way, but that was probably more about the tire size and gearing I had back then, along with the severe inability to change out more advanced items like differential gears. The one thing that was nice about it was having the ability to go to 4 Lock just by stopping and shifting the trans to Nuetral if I had the hubs locked.

If I installed manual hubs and locked them in for my long 2 hour drive to work, but left my truck in 2wd would it tear up anything? I know I can't drive long distances in 4wd.

 

[Ewhitaker0020]

Manual hubs are mechanical, controlled by you. Auto hubs have more moving parts, more parts equal more potential problems. But for most general use, with a stock tire size you would probably not have any issues as long as you keep them properly maintained. As far as leaving manual hubs locked in, that’s not really any different than what newer trucks do anyway. The front axle of all new trucks is always turning because the hubs are essentially always “locked”. The front differential just doesn’t get driven until the transfer case is engaged.
If it was me, I would keep the auto hubs until they began to malfunction. At that point I’d go to manual hubs. But as they say, if it ain’t broke, don’t fix it.

I think I will leave the automatic ones until they mess up or I notice that they're not working for my needs. Then I will switch them over until manual.

 

[RoryH19]

I have auto hubs on both of my k5's.
Like you, I will leave until they have issues then I will replace with manual.
The k20 I use to have came factory with manual hubs.

 

[idahovette]

The auto hubs will work fine until you really need them!!

 

[peats]

i would not wait for the auto hubs to fail. take the time to disassemble them, clean everything , properly lube everything, and put it back together. cost of a little solvent and grease and maybe 2 or 3 hours labor is time and money well spent.