4x4 problems...

1993 Chevy S10 Blazer 4x4 4.3L auto

4x4 suddenly stopped working. Checked and replaced transfer case vacuum switch, front axle 4x4 switch, vacuum actuator, checked fuses.

Still no 4wheel. The light on the lower panel signifying 4x4 doesn't come on as usual. Does this mean it is an encoder motor?

I checked the front driveshaft while in 4 wheel and it won't move as if in gear, yet the front wheels do not move under power. Someone mentioned about checking this. I can't remember if it was loose driveshaft=transfer case issue and driveshaft in gear=front axle problem. Can someone clarify this for me?

There is vacuum to the solenoid and it is pulling in the cable. I try to manually pull the cable to engage 4 wheel drive, but it doesn't. The tell tale sign of it not working is the little chassis light down by the 4 wheel shifter not lighting up. Any ideas?

Thanks

http://www.automotiveforums.com/vbulletin/showthread.php?t=572914
Put it in 4W
Jack up right front wheel and see if you can spin wheel.
If so the front axel is not locking in.

Is any shift indicater lights working or just 4W light not coming on?


Is this a floor 4W shift?

http://www.automotiveforums.com/vbulletin/showthread.php?t=572914
Put it in 4W
Jack up right front wheel and see if you can spin wheel.
If so the front axel is not locking in.

Is any shift indicater lights working or just 4W light not coming on?


Is this a floor 4W shift?

Thanks for responding.

It is a floor shift, basic 2W, 4hi, N, 4L. I had it in 4hi and low and couldn't turn the driveshaft, as if it were in gear. But it was on the ground. Later I'm going to jack the front and try this again. I was also thinking of disconnecting the vacuum actuator cable up top and down below, just to make sure that is not binding.

In the 93 style shifter down below, there are orange 'dot' lights to the left of each selector 2w, 4h, N, 4l. They light up as I shift into each one, and have remained functional always. It's the little chassis diagram to the right of these selections that is also supposed to light up the top/front part to signify it is engaged into 4 wheel. It stopped doing this and that's when I realized I had a problem with the 4 wheel.

Tell me what it means if (when I check the front):

if the right front does turn, while in 4hi?
if the right front doesn't turn, while in 4hi?

Thanks

Just wanted to add, make sure the car is running so you have vacuum. Jack up only the right front wheel, just enough to clear the ground. If it were me I would do it like this.
1. With car not running, in park and with parking brake applied place TC shifter in 2wd.
2. Reach under car and turn front drive shaft. If shaft turns free, things are good. If it binds or feels loose, check U-joints.
3. With car still off, in park and brake applied, jack up right front wheel just enough to clear, so it will spin.
4. Spin the wheel to verify it spins freely with no noise and is not loose or sloppy. Lower car.
5. With car still not running and in park, etc, place shifter in either 4wd mode.
6. Reach under car and turn front drive shaft. Shaft should not turn in either 4hi or 4lo.
7. With car still off, in park and brake applied, jack up right front wheel just enough to clear, so it will spin. Spin it to check.
8. Once you verified that wheel spins, with car still up on jack start engine. Check wheel to see of it will spin. With car running it should not spin. If it still spins, with engine running, shift into 2wd then 4wd again. Recheck wheel.
9. If wheel spins every time the front axle is not engaging. If it is not engaging check engine vacuum with gauge. Then check vacuum at front axle actuator, under battery. It should be very close to the same, if not exactly the same. If it is different, a vac line is most likely broken or leaking.
10. If good vacuum, turn off car and remove battery and battery tray.
11. Remove vac line from actuator and place finger over the hole where vac line was attached.
12. Compress the actuator manually while holding finger over hole. It should stay compressed. If not, it is leaking and will need to be replaced.
13. This is also a good time to jack up the front right wheel again and try to manually pull the cable and see if it locks in the axle that way. If axle still does not engage while pulling the cable the problem is in the front axle.

Duke 350
Has done a good job of explaining front axel lock in.

I think [not positive] the 4W light light on dash is hooked to a plunger type switch on front axel that turns on light when front axel fork locks in front axel.

Go threw the front axel lock in check.
Post back what you find.
Good Luck

All good advice and I am trying them in order. So far, I have jacked up the front, both fronts, all the way off the ground and had it in 4hi and 4lo while it was running and in drive. Being on the jack and snow all around, it was going nowhere. Both wheels turn freely. The driveshaft to the front is locked in, just like a normal driveshaft that turns only slightly left and right. I am now going to pull the cable off the actuator and the front axle port and see if it moves freely. I have a feeling it will, but will see. I'll also try the vacuum/finger thing too. I'm sure the actuator is good, but doesn't hurt to check once more. I'll post after I have done this and see what's next.

OK.

Feel I am getting down to the jist of it. I had the front up in the air. I pulled the cable from the actuator to the front axle, off from the actuator. Down below I unscrewed the cable from the axle, but it doesn't want to come out and I don't want to force it. Unsure how this comes out, since there isn't a manual available. Anyway, with the axle end of the cable still in, but unbolted, cable attatched..... I pulled harder than the actuator was.

Low and behold, the right front tire was rotating with some drag and the left front was rotating opposite the right front was. In essence, without the cable pulled, wheels move freely, independant of each other. With the cable pulled from down below harder, the wheels are moving opposite each other. I think this indicates that it is going into 4 wheel? Am I right? I am going to get a new cable ASAP and see if that helps matters. Can't find any shifter cables online, so must be a dealer item I presume.

I'll keep ya updated.
Thanks

Put new axle cable in. $45

Manually pulled cable and locked it for functional 4 wheel drive now.

Seems like it's too cold to engage or something along those lines. Anyway, plow on and did driveway. I'll wait till a warmer season to go through it fully.

Thanks for all the help.

You are welcome.
You are gaining on it.
Just do not drive it on dry payment locked in.
Let us know how it goes.