Dumb question about 4 wheel drive on my 72 C20

[Brettd85]

OK dumb question...

I have a 1972 C20 4x4, picture below. It has factory front locking hubs. If I put it in 4 wheel drive with the hubs NOT locked, will I still get 4 wheel drive? Well technically 1 wheel rear and 1 front since they are open diffs. Or do I have to lock the front hubs for the fronts to get any power? Reason I ask is its snowing here and I figure with front hubs locked it could be annoying on the street taking turns and things if I encounter some road without snow. Thanks for helping a dummy.

[too much stuff]

You will have to lock in the hubs to have 4x4. You can lock them in and run in 2wd until you need 4x4 if you want.

[Brettd85]

So did they never sell a 4x4 without front locking hubs? It appears as an option.

[dmack91]

GM had full time four wheel drive on the 73 and up trucks, but I didn't think they had it on the earlier versions.

[68panelman]

Originally Posted by Brettd85

So did they never sell a 4x4 without front locking hubs? It appears as an option.

I have seen 67-72 3/4 tons with just a drive flange on the hub.Many 4x4 spids have the option locking frt hubs.

[csb#356]

When it snows i drive around all the time with the hubs locked. If i feel like i will need 4wd I shift into 4wd then shift back out when i get out of the nasty area. I usually do this without stopping the truck. I might do this 5 or so times on the way to work and that is why i leave them locked, I can't realistically get out and lock them in every couple blocks and then get back out when I drive 50 yards and theres not any more snow. Therefore when theres snow on the ground leave your hubs locked in, When it melts and you dont need extra traction or your goin on the highway unlock em. Now is it going to wear out the front end faster. Obviously having the front axle turning is going to put more wear on it than having it not turning. You just have to decide wether or not that bothers you. Thats the best I know how to explain it. Good luck in the winter!

P.S. I never really have experianced the truck trying to jerk around when taking corners on dry pavement with hubs locked(in 2wd of course) unless turning about as sharp as you can or theres gravel or something. And that happens even when the hubs aren't locked sometimes.

[Brettd85]

Any reason not to drive year round with the hubs locked? but just in 2wd.

[Jerry Jones]

Originally Posted by Brettd85

Any reason not to drive year round with the hubs locked? but just in 2wd.

It is rough on the front end running gear to run with the hubs locked and on a solid no slip surface.

[Brettd85]

Isnt there still an open differential in the front end?

And why wouldnt you just drive around in 4wd all the time, but if you really needed 4wd, then lock the hubs?

[1972K20]

In those conditions, the best bet is to lock both front hubs, but leave the transfer case in 2wd or 2H until you needed 4wd.

[71blksuper4x4]

I am pretty sure it won't shift into 4wd without the hubs locked. Lock out hubs were an option. They came with driving flanges if not. Trevor

[vectorit]

You could have one hub sticking, since they over time get gunked up. Might be a good time to have them serviced?

Locked hubs on dry pavement in 2wd will put excessive wear on the hubs, and it will make the truck handle poorly causing irregular wear on the tires as well.

[Jerry Jones]

Originally Posted by 71blksuper4x4

I am pretty sure it won't shift into 4wd without the hubs locked. Lock out hubs were an option. They came with driving flanges if not. Trevor

The transfer case will shift into 4wd, but wont do anything with the hubs not locked, it will just free spin the front drive shaft and axles but the wheels wont drive without locking.

[Brettd85]

Originally Posted by Jerry Jones

The transfer case will shift into 4wd, but wont do anything with the hubs not locked, it will just free spin the front drive shaft and axles but the wheels wont drive without locking.

So again, why wouldnt we just run in 4wd all the time and if you want real 4 wheel drive, you lock the hubs?

[vectorit]

Once you try to parallel park on dry pavement in 4wd you will know why. Your tires will chirp, and the truck will jerk about.

Yes, lock the hubs to engage the front wheels.

Gas MPG will take a big dip.

[68 C-10 Panel]

Ok I might be able to help here... First i know you guys love pics so here is my 4x4...we call her "swampwater" anyway about the hubs locked or not the key thing for you would be the open diff in the front. If the hubs are locked and the transfer case is in 2w the front driveshaft is disconnected from the driveline. In this case as you go around a corner and the wheels travel different distances around said corner the driveshaft will rotate as the spider gears move. There should be no bind or load such as when there is a limited slip diff or worse yet a locker. if you put it in 4hi then the driveshaft will be forced to rotate and the pinion will follow but there will still be minimal bind ( only under acceleration ). So that may be alot of info but only use what you need. short story the hubs locked in 2wd should show no adverse wear. but be sure you have an open diff. oh by the way if you want to see this in action just throw the truck in 2wd lock the hubs and lift one wheel and rotate it you will see the front driveshaft rotate to allow for the difference in cornering .

[CG]

There is a thread on running with the hubs locked all the time and just shifting it into 4x4 when you need it and the consensus was it was fine to do. Thats how Ive been running mine (course I dont drive it much) lately and it seems fine. Let me find the thread and link it here for you...

Ok here is the link, its pretty interesting... http://67-72chevytrucks.com/vboard/s...d.php?t=431023

[Brettd85]

Maybe answer to my question is mileage. You are spinning more than you have to. Thanks for the comments so far gents.

[steelhorse]

You will get better gas milage and better wear on your tires if the hubs are unlocked.The truck will also accelerate quicker dur to less drag on the driveline.

[rayfinseats]

Dumb question? Maybe you should have said, "Hey I don't understand something."

In 4x4 it eats more gas. IN 4x4 with the hibs unlocked you are still in 4x4 but the front wheels are free-wheeling, which still uses SOME more gas.

You're welcome. It confused me too when I got my first one.

If the factories were trying to make good vehicles instead of pleasing the greedy stockholders they would all have positraction....2 cents.

[Altec]

Good info here. Maybe I can help get it all into one post.

Unlocked Hubs/2-Wheel Drive:
-Only the hubs spin. Drive shaft, and axle shafts do not turn. Least wear, and least drag on the system.

Unlocked Hubs/4-Wheel Drive:
-Drive shaft, and axle shafts spin. No power transfered to the wheels. Results in unnecessary wear on transfer case, ring and pinion, and axle shaft seals. also results in increased drag on your drivetrain. Lowering efficiency, and slightly higher percentage of power lose.

Locked Hubs/2-Wheel Drive:
-Same results as unlocked/4WD. More, or less. At full lock, or close to it some popping, and jerking can be felt in some cases. Result of the joints on the axle shafts binding.

Locked Hubs/4-Wheel Drive:
-Transfer case, drive shaft, axle shafts, and hubs all spinning. Increased wear, and lower efficiency caused by drag in the system.
-Dry surface use in Locked/4WD results in problems. Even with a open differential. The front tires are allowed to spin at different speeds, but since the front axle is now tied to the rear axle binding simply can not be avoided. Because the back of the vehicle will always take a different path then the front. The resulting effect is the "bucking" and other problems felt when trying this. The only way around this is with a transfer case with a built in differential. Options for this are slim. The popular choices are the NP203, and the NV245/247, and maybe a couple more.

[special-K]

I get binding in the '89 K1500 (IFS) I'm driving when I put it in 4wd just to back up my driveway. The road is clear and my driveway is snow & ice covered on an incline. I pull the lever just as I'm pulling in front of my house because it takes a moment to engage,pull past the drive enough,turn wheels,and back in. The steering wheel rocks back and forth and the truck is in an obvious bind. I have experienced this in every 4wd of every design that I have owned for the past 35 years. Before that,it was the Land rovers my dad owned since the '60s. I can't imagine someone not experiencing the same thing on dry pavement.

It just comes down to one very simple fact. It's best to use the system the way it was designed to be used...2hi/hubs free under normal circumstances and 4hi or 4lo/hubs locked when 4wd is needed or 2hi/hubs locked to 4hi for brief periods as needed. Heck,even when having a blast...4hi/hubs locked off road and throw it into 2hi to slide rear or just make a sharper turn...YEEHAW!!

[RustyParts]

Another reason to keep the hubs unlocked when not needed. The front axle is a steering axle and caster and camber is always adding and subtracting to the stresses on the axle.

[Brettd85]

Thanks for the comments guys.