Blazer 4 wheel drive problem

Ottawa, Canada

#183 Feb 17, 2011
I have a 2004 blazer 4x4 and it has recently developed a noise that gets worse as the vehicle speeds up. So far I have checked the fuel levels in the transfer case, both diferentials, the transmission and also the wheel bearings for wear. I am not able to find the problem/cause for this noise. The noise sounds as if the vehicle is in 4 high gear but it is actualy in 2 high gear. I have read some posts and there is mention of a vacum located under the hood on the firewal. It purpose is for locking the front axel. Just wondering whether this component could be the cause of my problem. Any assistance concerning this matter would be greatly apreciated. Perhaps someone that has had the same or similar problem would be willing to help me out. Thank you very much in advance.Richard

Ottawa, Canada

#184 Feb 18, 2011
Hello, Last Sunday I noticed that my Blazer was noisy. It sounded like it was either stuck in low gear or the 4 wheel drive was still on. The following day I examined it underneath and discovered that the front differential pinion seal was leaking so I imediately thought that the differential was low in gear oil and for that reason it was noisy. After having replaced the seal, re-filled the differential with 80W-90 gear oil, and changed the oil in the transfer case with Dextron III the problem was still there. I then checked the tires for possible faults, the vacum actuator thinking that the front differential was stuck in the lock position only to find that it proved to be locked in all 4x4 settings wth the exeption of the 2 high setting experimented with the vacum switch located on the firewall under the hood without any success. So having said this I was wondering whether the driveshft between the transfer case and the front differential should be engaged all of the time even in 2 high also wondering what else could be causing this noise. The noise is usually herd starting at aroung 40 kilometers and he loudness increases with speed. I am afraid to drive the vehicle above 60-70 clicks. Could it be that the vacum actuator cable is damaged within the differential, perhaps the transmission will not engage into overdrive (sounds like it is in 2nd gear)or maybee it is just a wheel bearing. I do not notice any slack when tryying to wiggle the wheel up and down as well as sideways. I have tried to remove the hub that the wheel bearing is mounted on and have been unsuccessfull even after removing the three bolts behind the hub. I cannot get it off it is like it is welded in plase. Maybee a special tool is needed? I have been at it now trying to fix my Blazer for 5 days and any comments or suggestion that might help would be tremendously appreciated. Thank you very much in advance.


Greensburg, PA

#185 Feb 22, 2011
I have a 2002 blazer. My problem is that when I press the 4wd hi or low the light engages but the wheels do not lock in. So even though it says it in 4wd my front wheel does not turn. Does anyone have any idea on how to fix it?

Ottawa, Canada

#186 Feb 22, 2011
Hello David,after having tried just about everything to find the source of my own problem with the noise, I suspect that by the description of your problem the solution lies in the actuator located under the battery. The rubber diaphram is probably pierced. Another posibility would be the vacun switch which controls the vacum going to the diaphram. If I were you I would remove the battery and the battery bracket and inspect the diaphram for any damage. Also unplug the vacum connected to the diaphram and make sure that there is vacum at the diaphram. To do this oyur vehicle should be placed in any 4 wheel drive setting with the emergency brake on or someone sitting at the wheel with his/her foot on the brake while in drive. I hope this will help you in solving your problem.

Good luck, Richard

Ottawa, Canada

#187 Feb 22, 2011
By the way David, the vacum switch is located under the hood dead center on the firewall and has 2 vacum tubes connected to it.

Richmond, IN

#188 Feb 23, 2011
I have a 2002 Chevy s10 Blazer 4x4
My truck has the 4 button switch panel rather than the 3 button my problem is that when i attempt to Kick it into 4wheel high is just sits there and flashes 4wheel low is the same just flashes as well with auto 4 wheel i have no clue what could be wrong when i Flip it into 4wheel low you feel it kick in but only the rear tires spin the front wheels wont lock into 4 wheel someone help me

Cambridge, Canada

#189 Feb 24, 2011
Hello Matt,Check previous posts and you should find the solution to your problem.Seems like you are not following first the neutral shift position for the 4wheel drive and your actuayor under the battery otr the vacum switch might be at fault. Try shifting in neutral then go to park then the desired gear.
dustin c

Schuylkill Haven, PA

#190 Feb 25, 2011
I have a 2002 chevy s-10 zr2 and it will go into 4x4 but it then kicks out in about 2 min any ideas

Southbury, CT

#191 Mar 3, 2011
i have a 2001 blazer none of the lights come on on the switch and 4 wheel drive dont work whats the problem
Richard C

Ottawa, Canada

#192 Mar 3, 2011
tony wrote:
i have a 2001 blazer none of the lights come on on the switch and 4 wheel drive dont work whats the problem
Sounds like you might have a burnt out fuse. Check the 4 Wheel drive fuse between the driver door and the dash.

Southbury, CT

#193 Mar 3, 2011
i have 2001 blazer push buton on dash the little lights that show you what 4 wheel position ure in dont light up and it dont go into 4 wheel drive

Saint John, Canada

#194 Mar 9, 2011
Did you find a solution to your problem, I have the same problem, I have a 95 blazer and cant get it out of 4low.

Southbury, CT

#195 Mar 10, 2011
the lights on switch do not flash they dont come on at all but lights behind them come on

Southbury, CT

#196 Mar 10, 2011
the lights behind that eluminate the words that say 4wh 4wheel low auto 4 wheel

Newmarket, Canada

#197 Apr 4, 2011
I discovered a fuse in the fuse panel under the hood and after i replaced it 4 wheel 2H 2low and 4 low changed with no problem ,,
Richard C

Cambridge, Canada

#198 Apr 4, 2011
Thank you John.

Annapolis Royal, Canada

#199 Apr 6, 2011
Miller wrote:
I have the same problem as ray-ray, i did the battery thing and it worked the first time. my only problem is i will be driving along and the button lights will start flashing and then it goes into 4 hi and i'm not even touching the button. this has happened to me three times and now it it stuck in 4 wheel again. I can go from 4 hi to low but it won't give me 2 wheel. any ideas??
I have 2000 S10 same problem it will shift from 4 hi to 4lo but no 2hi
Richard C

Ottawa, Canada

#200 Apr 7, 2011
John wrote:
<quoted text> I have 2000 S10 same problem it will shift from 4 hi to 4lo but no 2hi
Check your electronic Module located on the pasenger side behind the kick plate(shroud) on the right hand side.The conection could be rusted and a good cleaning might fix your problem. Make sere you dicconect the battery when you do unpug it and while you are attempting to clean it. Some dielectric might also help on the contacts. This is a conductive grease which will prevent the contacts from rusting. Hopefuly this will be of some help to you

Richard C.
Ben Miller

Hastings, MN

#201 Apr 10, 2011
Hey Guys, I have a 2000 Blazer LT and every time I put it into 4WHL hi or lo it locks one of the front wheels, like the breaks are on or something, what in the world could this be?

Beardstown, IL

#202 May 2, 2011
i have a 1991 chevy blazer, full size. the front left tire keeps trying to engage into 4wheel drive while driving. it makes a loud clicking noise. im trying to take it apart to see whats wrong. but i cant figure out how to take it apart. any tips or links?

Tell me when this thread is updated:

Subscribe Now Add to my Tracker

Add your comments below

Characters left: 4000

Please note by submitting this form you acknowledge that you have read the Terms of Service and the comment you are posting is in compliance with such terms. Be polite. Inappropriate posts may be removed by the moderator. Send us your feedback.

Chevrolet Blazer Discussions

Title Updated Last By Comments
2001 Chevy S-10 Blazier fire (Sep '06) Oct 21 Jgrahamz 29
1998 Blazer Heat/AC Problem (Mar '07) Oct 19 Sage 132
97 Chevy Blazer Will Not Start (Nov '06) Oct 17 Dorothy 197
News Ask the Auto Doctor (Mar '06) Oct 9 Alnilam2206 1,545
2002 blazer vacuum lines (Jun '09) Oct 7 Old girl 19
Blazer ran out of gas and won't start (Oct '15) Oct 2 BlazerJames 4
rear end gear oil what type to use? Sep 28 BlazerJames 1
More from around the web