humming noise r/f

98 blazer humming noise in r/f. goes away in 4 wheeldrive, I think !! Any common problem????

One question does the humming sound resemble the noise heard when a truck has over sized tires on it driving down thee interstate. Ok two questions, does your humming go away when you turn the wheel in one direction an seem to get worse in the other, if so you just bougt yourself a new front hub assembly. the bearings are shot. the kicker is it a bit pricy, easy to acomplish by yourself in the driveway, if you need some detailed instuctions let me know, but buy the piece as a kit, I believe it the bearing hub assembly. Good Luck!

One question does the humming sound resemble the noise heard when a truck has over sized tires on it driving down thee interstate. Ok two questions, does your humming go away when you turn the wheel in one direction an seem to get worse in the other, if so you just bougt yourself a new front hub assembly. the bearings are shot. the kicker is it a bit pricy, easy to acomplish by yourself in the driveway, if you need some detailed instuctions let me know, but buy the piece as a kit, I believe it the bearing hub assembly. Good Luck!
Already replaced wheel bearing!! I'm an auto tech, heard something about 4wd problems, just wondering if any body knows of any common problem. Noise comes and goes, never there in 4wd! THANKS

hey i have an 89 blazer and i am hearing the same humming noise what is it and how can i get it to go away

I just bought a 99 blazer 4X4 2 months ago. 81000 miles, and last night going home, mine started making that grinding/humming noise in r/f at highway speed. If I sped up, it quieted. When I let off the accelerator, it got louder. When I slowed to turn onto my road, the noise slowed with speed and went away at about 20 mph and didn't make any more noise the rest of the way home. Any ideas would be greatly appreciated..

I'm the guy who originally posted this,I'm also an ase certified tech! The noise won't happen in 4wd or on the lift,it's not the wheel bearing! IT'S DRIVING ME NUTS!!!!!!!!!!!!! HELP!!!!!!!!!!!!!!!!

I just encountered the same problem with my 1996. Anyone find the solution yet? Seems like the front diff is not fully disengaging and the gears are making noise. Not sure which part is to blame?

OK Beerman is on the right track! I did a bit of road testing, speed at which noise is present varies(usually 50-55) seems to lessen if not totally stop if shifted into 4wd. When shifted back into 2wd noise returns, in a big way then lessens. I think there is an acctuator on the axle but have not checked it out!!! I would rather push my CHEVY, than drive a FORD !!!!!!!

Thanks for your help Glen. I changed the vacuum switch on the transfer case and that did it. Its on top of the case and has 3 vac lines plugged into it. Just take the lines off use a 7/8 wrench and change the switch. Its a little tough to get at but you can do it without taking anything apart. Cost $15 and fixed mine. There is a ball in the switch that opnes and closes allowing vacuum to be transfered bewtween the lines. Ive heard these balls stick and that will cause it to either not engage 4wd or in my case not disengage. I hope this helps ...let me know if you need anymore info on it.

i wonder...mine didn't make the noise today.
i played with it a bit, switching in in and out of 4wd.
maybe it knocked the ball loose?
where did you get the part? used?

What part? I haven't done anything yet!!! I did however notice today that my 4wd didn't work( it snowed). The vacuum connecter fell off the switch on the transfer case,mabey that had something to do with it. Probably not, I'm not that luckly!!!! Mine blazer didn't or doesn't make the noise all the time either! If by some strange chance the vacuum issue resolved the problem, I'll let you know!!!!!

I was having problems with 4wd engaging on my 97 Blazer. The lights would flash once and then stay in 2wd. I just changed the vacuum switch (the old one of which was really worn out). It is now stuck in 4wd. The lights on the dashboard switch no longer respond at all -- no clicking sound, don't even light up. Can anyone help?

Just for peace of mind take the vac switch out shift into 4wd and the back into 2wd and reinstall the switch. I'v seen them installed and stick, also check the ball on the switch while its out for sticking!!!

I would try switching in into 4wd & back to 2wd with the switch off, but I can't even get the dashboard controls to respond anymore. I remember that there was another clicking sound lower in the dashboard when the controls did work. Is there another relay fuse or something else within the dash that might have shorted?

To be honest with you, I'm not sure exactly how the system works. Still waiting to recieve my FACTORY service manual. The click under the dash is a relay,I'll contact someone tomarrow and see if I can get the wiring diagram faxed to me and let you know. sound good???

Sounds excellent. Thanks!

autoengine I'm still working on getting the wiring diagram!!! Hang tight alright bud!!!

no problem. I'm just hoping to have it figured out before the next snowfall, which is looking like the first part of next week here in MN

no luck yet with diagram, sorry I'm trying

98 blazer humming noise in r/f. goes away in 4 wheeldrive, I think !! Any common problem????

Glenn, I have the same problem with a 2000 blazer, I have replaced both hub assemblys and the switch in the top of the transfer case. The vehicle still makes the noise and I am also going nuts chasing the fool thing. It goes away with the 4wd on. Have you had any sucess finding the problem. I would appreciate any help!!!!!Thanks

Jethro informed me that he had the same problem and it was the actuator for the front axle!!!!!! Autoengine, no luck with the wiring diagram,sorry. I know there is a relay behind the glove box, I think its behind the glove box. If I had to guess the switch probably grounds the relay which in turn powers the control unit and engauges the transfercase which then sends vacuum to the actuator under the battery and locks the front end. Wish I could be of more help!!!

I've got the same sound in my wife's '99 blazer. Haven't worked on the Chevy much, where can I get the vacuum switch and where can I get the hub assembly? Online or do I have to order through a dealer? How hard is it in the Blazer?
Thanks.

I have a 2000 4X4 blazer with a 4.3. I too have the noise in the front end. Go to 4h and it goes away (from 4L). Have you figured out what it is yet? I was thinking of changing out the valve on top of the tranny- like the other guy did in an earlier response. Any other updates around this? So frusterated. :banghead:

I have a 98 Blazer and it also makes a loud humming noise and as I speed up it gets louder. I tried switching it over to 4wd hi it worked for a second but then it gets louder. When I hit bumps on the road it goes away but then returns when I get back on flat land. Anyone have any ideas what it could be?

I'm having the same problem here on a 97 Blazer with only 50000 miles. It has the 4.3 with the 4X4. Is the solution the vacuum switch? I was wondering if the problem might be that the 4 wheel drive is switch by itself into 4 wheel Low? Anyone have an update on this one? Thanks.

shootsnlad

No not yet. It's a common problem hey.

I was reading on another site that someone posted this same problem. The person there also said it was the vacuum switch that is the problem because it controls the front axle and that it is known for sticking. If it sticks it will try to engage the front axle, especially when you decelerate. I'm going to have it replaced tommorrow. Thanks.

Let me know if that works Shootsnlad or if you could just post it up here. The noise is driving nuts!

I did some test driving last night and I noticed that when I was driving and I turned the steering wheel left, the noise went away.

I did some test driving last night and I noticed that when I was driving and I turned the steering wheel left, the noise went away.

If you turn the wheel to the left you are putting more weighton the right front wheel, and if the noise is gone then you probably need a left front hub assembly. The noise that seems to be associated with the front differential seems to be a noise from the right front . Is the noise a hum that gets loader with speed?? I didn't read all of your entrys so if you already stated it , sorry.

Hey just picked up my blaze from the body shop no the drive home the noise returned and its snowing so I said to my self time to play. Popped it into 4WD and noise gone, back into 2WD, a couple minutes later it came back,back into 4WD noise gone, back into 2WD noise gone. Slowed to about 30 mph noise kind of went away, back up to 50+ mph and all of a sudden the noise is back. Noise also changes as the R/F suspesion travels through its stroke. All noises are caused by vibration, I'm begining to wonder if the R/F shaft or R/F axle bearing is where the problem lies. This weekend I'm going to run it with chassis ears to try to pin point closer to the cause. I'll let ya all know. Till then turn up the radio!

Rocky Z that sounds right. Yes the sound does get louder as I speed up the wierd thing is when your in the car it sounds louder on the passeger side then the driver side.
Glenn Peters-I tried to switch it into 4wd hi and the sound goes away when I first engage it and then it comes back full strength.

THANK GOD!!!!!!!!!!!!!!!!I took my blazer in to adjust my torsion bar to level out my car and they noticed that my "Right front hub assembly" was shot and I needed a new idler arm. After replacement, the car runs smooth. Now this worked for my situation good luck. By the way, it cost me $645 to get it fixed but it was worth it for my sanity.

I replaced mine, wheel bearing that is. Not the problem. Glad to hear your problem is solved.

Sounds like there are a couple of different issues with all these vehicles. Some are the hub/bearing, and others sound more like vac/ electrical issues. I recently took my 99 Blazer on a road trip to Kansas City. (325 miles) Before then, I had only experienced the noise once. On the trip after about 50 miles, it started making the noise at 75 mph in 2wd. As I let off the accelerator, the noise got louder, and when speeding up it quieted. I slowed to 60mph and switched to 4hi and the noise immediately went away. Back to 2wd and it started right back. So I switched to 4hi and drove for 4 or 5 miles and switched back to 2wd. This time I noticed a noticable clunk as it switched back to 2wd. I had no more noise the rest of the way up there or back. Upon getting home, just for kicks I put it in 4wd for a little off road. As soon as I got back on the highway and put it in 2wd, the noise came back. Switched to 4wd for 4 or 5 miles, back to 2wd (noticable clunk again) and no noise for the last week. I think mine is the issue with the vac/switch sticking. I am going to try that when I get some days off. Sorry so long winded, but this is just my experience with this annoying problem.

Sounds like there are a couple of different issues with all these vehicles. Some are the hub/bearing, and others sound more like vac/ electrical issues. I recently took my 99 Blazer on a road trip to Kansas City. (325 miles) Before then, I had only experienced the noise once. On the trip after about 50 miles, it started making the noise at 75 mph in 2wd. As I let off the accelerator, the noise got louder, and when speeding up it quieted. I slowed to 60mph and switched to 4hi and the noise immediately went away. Back to 2wd and it started right back. So I switched to 4hi and drove for 4 or 5 miles and switched back to 2wd. This time I noticed a noticable clunk as it switched back to 2wd. I had no more noise the rest of the way up there or back. Upon getting home, just for kicks I put it in 4wd for a little off road. As soon as I got back on the highway and put it in 2wd, the noise came back. Switched to 4wd for 4 or 5 miles, back to 2wd (noticable clunk again) and no noise for the last week. I think mine is the issue with the vac/switch sticking. I am going to try that when I get some days off. Sorry so long winded, but this is just my experience with this annoying problem.

Hey, I think you are on to something. I believe that maybe at the higher speeds the actuater is moving the front drive axle out of 4wd a little farther than when at slow speeds. My 2000 blazer has the exact same problem and when it gets real noisey and obnoxious I switch to 4wd and back out at a higher speed and it makes a difference but doesn't eliminate it. I haven't tried it at 60mph because when I look at the front axle it reminds me of the one on my garden tractor(not big enough for the job). I am going to put synthetic fluid in mind as soon as it warms up a little and see if it helps. If you find out the anser please let me know and I will do the same. :banghead:

Hi Guys
I have a problem with my Jimmy NOT going out of 4wheel, it wont go into 2w or 4 low either. When the engine is off and I press the botton with the key turned on, I hear a electrical motor sound coming from the transfer case. When button pressed on dash, it just flashes on 2w and goes back to the 4w drive. What do you think the problem is?

wow must be alotta people are having 4X4 problems, well mine just dosen't like go in to 4x4 i usally have to wait an reverse foward, then it finally kicks in

Mine too. Loud tire sound during acceleration quiets when coasting. Noise changes as I ride over highway mounds. 1998 4.3 Blazer.


QUOTE=Jdizil]I have a 98 Blazer and it also makes a loud humming noise and as I speed up it gets louder. I tried switching it over to 4wd hi it worked for a second but then it gets louder. When I hit bumps on the road it goes away but then returns when I get back on flat land. Anyone have any ideas what it could be?[/QUOTE]

mine still does it intermittantly.
it seems like if i switch in and out of 4wd, it goes away.
i recently raplaced ball joints, idler, and pitman arms, they were all worn, and had nothing to do with the noise i guess.

I have been thinking on this for months, just listening and trying different things. When you hear the noise you can feel a vibration. Put into 4wd the noise goes away(for the most part). The noise doesn't always happen. Hmmmmmmm. I replaced the ball joints in my Blazer, the noise is some what worse. The noise now changes pitch during suspension travel(some one had posted that theirs did that). I believe that the noise is a CV Joint on the right side, probably the inner. My noise doesn't change with steering input. Not sure when I will replace the axle shaft/cv joints. If some body wants to give it a shot on their ride, Let us all know how it turns out.

I have the same issue with my 2000 blazer. I also noticed when I turn to the right the noise goes away. When I turn to the left it is load as ever. These turns are done at 30+ mph on a sweeping corner. It is driving me nuts!! Thank goodness the stereo is good in this vehicle.

that sounds like you have a possible wheelbearing issue

hi this may sound simple but check your tire pressure,or the tire itself for damage (broken belt) the other issue that we have is a worn c.v. axle assembly. good luck jj.

nope, it's not a tire, in my case anyways. i rotated them , and made sure they were properly inflated. still the same.

hi. don't forget to check your axle some do wear in one spot and after a fromt end allignment they make noise,if not i'm stumped ,good luck jj.

A humming sound was coming from my front end when I would have the wheel slightley to the left. Right, it would go away. Problem was a noisy right wheel bearing. The dealer kit was $388.74 and the labor was only $70. Fortunately, I have a 3rd party extended warranty which called for a $100 deductible per visit. (Racked up a $863.57 total this visit. Yeah warranty!)

Hey all.....about 3 days ago My 2000 Blazer started making a slight humming noise somewhere in the driveline. I'm not sure where yet but it feels like the front diff is engaged and is creating a drag of sorts. it doesn't coast near as well as it used to. however, the noise is present in 2 and 4 wheel drive. Also, my 4WD switch works fine as far as engaging and disengaging. I get no signals and the front end binds up at full steering lock (like normal) in 4WD. The brakes aren't dragging and I can't think that any suspension joints would cause this anyway. Also, when parked I can turn the front driveshaft freely with my hand so I'm assuming that the front diff isn't engaged in any way. It doesn't seem that the front u-joints are worn out either. I also checked both sides of the front driveaxles for wear and tear on cv boots but they look great so I'm assuming that the cv joints are ok as well. I haven't checked the rear u-joints yet but I've got it scheduled to get a tranny service and the guy said he'd look at the u-joints as well. I DO :screwy: however, have some play as far as when the transmission is initially put under a load, it does clunk, and I can get it to do the same pretty hard if I let off the gas when cruising and then push back on it. The initial load clunk is actually intermittent, but it happens enough to cause some worry.

IF.....anyone has had similiar problems or I've opened up an avenue of thought not yet approached on this matter, please let me know. It seems that this may not be as serious a problem as thought seeing as how alot of you seem to have had this going on for quite awhile.

It doesn,t sound like what I hear. Does the noise change in tone or pitch as the suspension travels ????

Well.....I got to thinking about it and no it really isn't the same as yours I guess. The pitch doesn't change with anything really. You can't hear it as much as you feel it. It's most noticable from 30-45 mph. Then you can tell something is holding it back. It doesn't matter whether it's in 4WD or not. When you take a sweeping turn to the right (cloverleaf exit) it feels a little more noticeable as well. There's no clunking or death sounds yet (knock on wood).

where do you feel it, in your feet, in your but, in the steering wheel. Are you sure its not stuck in 4wd

Ok, I started it up and while running in Park, the front driveshaft will still turn with my hand easily, so I'm pretty sure the front diff isn't engaged. I feel the vibration/grinding in the steering wheel and in the brake pedal. I'm not too sure on how to tell if the hub(s) has/have cratered on me or maybe if a ball joint has went south and has offset something. :banghead:

How much do hubs usually run? I know the labor kills on ball joint repair/replacement so I may try to do it myself if that's the problem. I've got access to a shop with the right tools. I haven't jacked it up and tested ball joints yet or pulled the wheel(s) and looked at anything yet.

Hubs/wheelbearings should get louder on turns. My inner cv joint is bad on the right side and you can feel it in your feet. Hold the inner joint and see if there is any play when you move it.

Hey- not sure if this is related to your problems but i had a humming noise in my 98 blazer. Usually happened at higher speeds (50-85) and I checked a lot of things. Sounded like road noise from tires almost but didn't change when going over bridges, etc. One day I had a buddy with me and it did it... he told me it was the luggage rack!! I pulled over and we moved the bars to the middle close together and tightened them down good... and I haven't heard the sound since (5 months). 1 1/2 years of going crazy from the noise all because of a luggage rack!!! Hope this might help someone.

Replacing my R/F hub bearing assembly corrected the problem for me (cost $163).

may want to check wheel bearings

Is there anything new on this? I to have this problem with my 2000 4x4.

I replaced my right front hub ($160 @ Advanced Auto) and it fixed mine. Just got the cooling system flushed and filled too for $50. Everythings doing ok right now. Just waiting for the next POS on this POS to go bad so I can dump more money into it.

This is in relation to old posting of blazer R/F humming noise. My 2000 blazer Had it in the left front. After an alignment and new tires it was still humming it's tune. Well jacking up the front end and puliing the left tire top to bottom revealed a loose bearing. Replaced it with the hub assembly and it is now as quiet as the day I bought it. I got it at advance auto for $135 + tax.

I just bought a 99 blazer 4X4 2 months ago. 81000 miles, and last night going home, mine started making that grinding/humming noise in r/f at highway speed. If I sped up, it quieted. When I let off the accelerator, it got louder. When I slowed to turn onto my road, the noise slowed with speed and went away at about 20 mph and didn't make any more noise the rest of the way home. Any ideas would be greatly appreciated..
Hi my name is john the noise is the axle bearing going bad