Hey everyone, I have a 2000 S10 Blazer, and the front axle isn't engaging. I was on the edge of a driveway, with the rear tires on snow and the front tires on dry blacktop. I had the transfer case in four high. The rear tires just spun. I can hear the solenoid, when I go from two wheel, four high and four low. I am going to stop at my mechanic after work tomorrow. I was just curious if anyone else had this happen. Also, I have a whining noise on the highway in four high. But not in two wheel drive. Thank you.

 

Sounds like the sleeve on the front axle disconnect is not engaging the right front axle all the way. thus giving you the whining sound.

I would check that by raising the right front wheel off the ground, start it up, put it in PARK and 4HI and see if you can move that right front wheel.

It should move a little each direction but stop. If it does, the front axle is locked in.
If not, could be the vacuum issue, or even a bad sleeve in the front axle disconnect.

good luck,,

 

Along the same line as was suggested by okaussie, put the vehicle in 4hi, and see if you can turn the front driveshaft by hand. If the transfer case is engaged properly you will not be able to turn the front driveshaft. If it is not engaged (or in 2hi) then the front driveshaft will spin freely. This will let you know for sure that the issue is related to the front differential.

Most likely okaussie is correct and the sleeve is not properly engaging the front differential. This is controlled by a vacuum solenoid under the battery. Following the test procedures described by okaussie, if in 4hi you can still spin the front tire, try squeezing the solenoid by hand to pull the cable (you will likely need to move the battery to access the solenoid). If pressing the solenoid by hand engages the front differential then the problem is insufficient vacuum. Quite possibly caused by a vacuum hose being disconnected or dry rotted and leaking.


There's tons of discussion and write-ups in the tech how-to sections on this.

 

In my case, by raising the right front wheel off the ground with the engine off and in 2hi I pulled the cable by hand and I heard it "Tick" and felt it in the cable. Mine does this only when I move the tire in the forward direction. When I try to move the wheel in Reverse, it locks up like it is suppose to.

By feeling and hearing the ticking I am 99% sure it it the front axle disconnect, probably the driven gear and or sleeve, in the disconnect. There is a kit on EBAY you can get for this problem and totally rebuild the disconnect assembly.

That is what I intend to do shortly.

 

Thank you for the advice. I have the Blazer jacked up. The transfer case is in four high. The front driveshaft does not move. The right front wheel does turn. A buddy said it might be the solenoid on the axle. Another friend, said it might be the vacuum switch under the battery. I have the battery out, but I cannot find the switch. Also, where is the switch of the front differential? Thank you.

 

Is this boot supposed to be ripped? I'm guessing not. Could this be the problem? I miss the old 4x4's, a lever, linkage and an actual axle. That would be an easy fix.

 

That is probably going to be the culprit.

Your front axle is not engaging due to the front axle actuator not pulling on the cable that goes to the front axle disconnect in the differential.

The tear in the actuator in your photo proves 99% that is the defective part.

Vacuum goes into the actuator to pull the cable. When you have a tear, the vacuum is not created due to that leak, thus not allowing the cable to be pulled.

Easy fix, just replace it. I would also replace the cable while you are at it. It might save you time down the road. That cable is prone to freeze up and not engage the front axle or even break in two. It is easier to replace it while you are doing the actuator.

Good job,,

Bill

 

I replaced the actuator yesterday. It wasn't too bad to do. The hardest part, was getting my hand into the the corner, and getting those three little screws in. It is really nice having the front wheels turning again. I really do appreciate everyone's advice. I would have been lost without your help.

 

Glad we could help. BTW, did you replace that cable too??

Bill

 

I have good news and bad news. The four wheel drive is working. But, I was driving to work last week. I got on the off ramp, and I heard a whirring noise. The noise decreased as I slowed down. Then as I accelerated, the noise would increase. I had it in four wheel drive. Once I got on the highway, I put it in two wheel drive. As I got off the highway, I put it in four wheel drive, then back too two wheel drive. The noise went away. A couple of days ago on my way to work, the same noise happened again. It had been a couple of days since I had the Blazer in four wheel drive. I did the same thing as the other day, I put it in four wheel drive, then back to two wheel drive. The noise once again stopped. Now, I've had this noise happen in the past. One of the guys at the junkyard told me about the reservoir on the fender. He said to get an inspection mirror and to see if the vacuum line was off. Sure enough, it was off. I put the line on, got the Blazer on the highway and the noise was no longer there. When I first started this problem, I checked the line on the fender. It was on. Bill asked if I replaced the cable. I did not. The guy at O'Reilly's said, if the cable feels smooth, it should be fine. But, if the cable was tough, or difficult to pull, then I should change it. So, I am wondering what is my next step to stop the noise. I though about taking the battery out, and checking that the vacuum line is secure on the actuator. I am sure that it was tight when I put it back together.