1989 Chevy 1/2 ton Suburban 4X4 - HELP!

Ok, I purchased this thing with the idea in mind of making a snow plow out of it and occassional road driving, etc.
When I purchased it the rearend was out.
I recently replaced it and it works fine. However, the 4 wheel drive I do NOT understand nor does it seem to work correctly.
If the vehicle is sitting on ice and the back wheel/s spin and you put it in 4X4 it should cause the front hubs to lock in and away you go.
Im used to the older type 4X4's and away you go!
This thing will not move, the front drive-line just spins and the hubs do not lock in, so I rock it back and forth and "occassionally" you can feel the front hubs wanting to lock in or jerking, then after several mins of fooling around, it will sometimes lock in and away I go, like one should after putting it in 4X4.
MY QUESTION; Is there something wrong or is this normal? Are the front hubs electronically controlled or is something worn out in them that causes them not to lock in and work correctly? I do NOT like things the way they are now and it is worthless as a 4X4, imo.

Idea's and options please?

My guess is that most auto hubs are destroyed by operators who do not understand how they engage or think they are engaged and then put the hammer down.

For the auto hubs to lock the front driveshaft must turn. While driving down the road this is not an issue because the front tires are rolling along at the correct speed. When stuck the front tires are not moving and to engage the hubs you'll have to spin the rear tires so the driveshafts turn. The hubs now engage under load and they have to withstand the forces required to start spinning the front tires from a dead stop. If you are too aggressive with the throttle during the engagement, then bang goes a hub. Simple as that. A friend went through a couple of auto hubs that way.

Nothing really wrong with the auto hubs, but if they need replacement, manual hubs are the way to go for all the reasons already stated.

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Got this from a fullsize gm 4x4 forum I look at. Most people there prefer manual hubs to auto because you KNOW your hubs are locked (which seems to be the problem). If your driveshaft is turning, then perhaps your hubs are damaged.

There really isn't much to your 4x4 system: when the transfer case is in 2wd, only the rear shaft should turn, in 4wd, both should turn, but you need to lock or unlock the hubs. The hubs are not electronically controlled, but the auto hubs are more prone to failure (mostly because of how they engage/disengage) and you generally won't know until you need them that they have. Manual hubs you simply need to get out and lock/unlock them when you need to. All that is required to convert from auto to manual are the hubs themselves.

Great, now I need different hubs.. If I have to get some, they will be lock-in-out types.
This other crap is a waste of time..

One guy told me there is an electrical or vacuum until called an "acuator".
I cant find it though, so its probally not there and its just the hubs.

Hubs

I had the same problem, I am willing to bet that it is the acuater. It is a simple fix and there is a way to test to see if in fact this is the problem.

ChevyMitch said:

Great, now I need different hubs.. If I have to get some, they will be lock-in-out types.
This other crap is a waste of time..

One guy told me there is an electrical or vacuum until called an "acuator".
I cant find it though, so its probally not there and its just the hubs.

Click to expand...

hubs

The actuater has oil or something in it that heats up and pushes a plunger in and engages the front diff. Sometimes these could take up to five mins to engage as they get older or the weather is cold out.On mine ther was a black cylender like thing on the pass side just to the left of the diff behind the axle. there is a wire running to it, You can engage the trnsfer case and put a paperclip in both sides and use a test lite to see if you are getting power. If you are the the actuater is junk.I put an upgrade kit on mine that has a wire that runs to the transfer case and engagement is instant.Also the light, if the bulb is good, should come on in the four wheel drive lens on the floor where the shifter is.

Mine are the auto-hubs and are just getting worn out, so Im told anyway?

The " manual lock-out conversion kit" is going on this Spring.

Thanks...

Have you tried shifting from 2H to 4H while the truck is in motion, 4 mph or less, shifting through neutral from 2H to 4L also while rolling, with your foot off of the gas pedel, turn the dash light dial to high to see if the shift lights are working. See pages 2-32 to 2-34 in Owners manual.

This sounds Shifty to me!

Ski

ChevyMitch said:

Mine are the auto-hubs and are just getting worn out, so Im told anyway?

The " manual lock-out conversion kit" is going on this Spring.

Thanks...

Click to expand...

auto hubs suck the big one, maunal hubs rock and slugs are the win for the lazy and cold.

THIS TRUCK DOES NOT HAVE AN ACTUATOR!!!!!!

that is only on ifs trucks[88+] burbs and blazers[92+]