OT/ 87 Chevy S-10 4-wheel drive wont lock in?

Balaton17 · Jan 7, 2009

The Gear box of the trany is good and I just replaced the switch that is suposed to engage the front axle. I think that its an eletrical problum but I'm not sure. The light comes on in the cab that says its engaged but it wont lock in. I'm stuck on this and open to ideas.
Thanks for the help.

Mark W. · Jan 7, 2009

If this is the push button system there is a very good chance there is a leak in the vacuum line. This was an issue on my blazer until i found a leak in the line and spliced a piece in it. No problems after that.

S.Crum · Jan 7, 2009

With your engine running, pull your transfer case into 4WD. There's a vacuum actuator on the right inner fender under the hood that engages the front end, this should be pulled in by engine vacuum. If it's not, you either have a bad vacuum switch on the transfer case or a bad vacuum line. Check for vacuum at the actuator, if it's about the same as the engine vacuum and the actuator is not pulled in chances are the actuator is bad. If the actuator is pulling in all the way and still not working, you'll need to go into the front end. Check the actuator cable first to be sure it's not broke or disconnected. My 85' S-10 Blazer had a bad vacuum switch on the transfer case.
I was able to get home one night with a C-clamp holding the actuator in.

Allan in NE · Jan 7, 2009

Uf-Da! 87? Trying to remember. :>(

Seems to me that there is a vacuum actuator mounted on the right inner fender panel right behind the battery.

It's usually the vacumm feed to that actuator and you'll more than likely find a bad hose back behind that right head.

Hope I have my years straight......

Allan

Balaton17 · Jan 7, 2009

The shifter is on the floor, and I'll check the vacume lines after school. Thanks for the help.

bradk · Jan 7, 2009

Is the switch that you replaced on the front diff? That's the switch that sends power to illuminate the 4WD indicator when the front gears in diff are engaged.

Theoretically, if the 4WD lamp is on,the front gears are engaged.Do you have a broken CV axle in front? Put the truck on jack stands. Does front output shaft from t-case spin when in 4WD and running in gear?

Balaton17 · Jan 7, 2009

Yes, Here is a pic the switch I replaced on the front dif, The light still came on that said it was locked in before I repaced it thoe, and the new one didn't make a diffrence. Thats where i'm stuck.
I'll check the actuator and vacume lines after school and go from there.
Thanks again for the help.
Balaton17
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Anonymous-0 · Jan 7, 2009

where are you? Could it be the hubs themselves froze up? If you can swing a set of manual locking hubs, it'll save you a whole lot of grief. That's if the transfer is working and putting power to the frt end.

Dave

Anonymous-0 · Jan 7, 2009

isnt there a switch on the trasmisson, had a 89 with 5 speed and changed at lest 2 times!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

gab · Jan 7, 2009

Look for a vacum line leak around the right rear of the engine in the line to the frt. actuator or the three port vac. switch on left side of transfer case above the drive shaft.

Balaton17 · Jan 8, 2009

Thanks guys, Found the problum, (Vacume line came loose). Thanks for the help.

OT/ 87 Chevy S-10 4-wheel drive wont lock in?

Balaton17

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Mark W.

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S.Crum

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Allan in NE

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Balaton17

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bradk

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Balaton17

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Anonymous-0

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Anonymous-0

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gab

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Balaton17

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