2000 Blazer 4x4 issue
#1
07-11-2019, 07:09 PM
2000 Blazer 4x4 issue
Hello all,
Attempting to diagnose a 4x4 related noise I have, looking for some guidance. It's pretty straight forward, when I engage the 4x4, everything is fine and there's no noise, but when I turn in either direction there's a loud clunking noise, and then when I go back straight it goes away. Doesn't matter if I'm on gravel or pavement, it's the same. One weird thing I've noticed is that it doesn't always go away when I get back into 2WD, sometimes it takes a few miles or even a few days to go away, but it does always eventually go away when I'm back in 2WD. Any information is greatly appreciated.
Thanks,
Dustin
Attempting to diagnose a 4x4 related noise I have, looking for some guidance. It's pretty straight forward, when I engage the 4x4, everything is fine and there's no noise, but when I turn in either direction there's a loud clunking noise, and then when I go back straight it goes away. Doesn't matter if I'm on gravel or pavement, it's the same. One weird thing I've noticed is that it doesn't always go away when I get back into 2WD, sometimes it takes a few miles or even a few days to go away, but it does always eventually go away when I'm back in 2WD. Any information is greatly appreciated.
Thanks,
Dustin
#2
07-11-2019, 10:41 PM
Welcome to the forum!
For starters, don't put it in 4wd on pavement and turn, that's asking for binding and breaking... basic unmodified 4wd isn't meant for pavement, it's meant for loose ground (off road use)
It sounds to me like you have either a front diff or axle issue.
Put the front of the truck in the air on jack stands. Start it and put it into 4wd, but leave it in park (chock the rear wheels and/or put on the parking break if you want to feel more safe). Doing this will engage and lock in the front diff. Now try to manually (by hand) rotate one of the front tires. This is going to get the gears in the diff and the axle shafts (while they've also got some angle at full suspension droop) moving. See if you can hear or feel any of the clunking or popping noise while rotating them. If not while the wheels are pointing strait, trying turning them left and right, still while it's up on jack stands, still while it's running, in park, in 4wd, and see what the results are.
IF there's no noise after doing this, my next guess would be some very worn suspension components, like ball joints or control arm bushings, but that noise won't usually go away like you're describing...
Once you can replicate the noise in a controlled environment, you can begin to track it down a little better at least.
I used this similar method to track down a bad wheel bearing on a 2 post lift :P
For starters, don't put it in 4wd on pavement and turn, that's asking for binding and breaking... basic unmodified 4wd isn't meant for pavement, it's meant for loose ground (off road use)
It sounds to me like you have either a front diff or axle issue.
Put the front of the truck in the air on jack stands. Start it and put it into 4wd, but leave it in park (chock the rear wheels and/or put on the parking break if you want to feel more safe). Doing this will engage and lock in the front diff. Now try to manually (by hand) rotate one of the front tires. This is going to get the gears in the diff and the axle shafts (while they've also got some angle at full suspension droop) moving. See if you can hear or feel any of the clunking or popping noise while rotating them. If not while the wheels are pointing strait, trying turning them left and right, still while it's up on jack stands, still while it's running, in park, in 4wd, and see what the results are.
IF there's no noise after doing this, my next guess would be some very worn suspension components, like ball joints or control arm bushings, but that noise won't usually go away like you're describing...
Once you can replicate the noise in a controlled environment, you can begin to track it down a little better at least.
I used this similar method to track down a bad wheel bearing on a 2 post lift :P
Last edited by blazen_red_4x4; 07-11-2019 at 10:44 PM.
#3
07-12-2019, 12:00 AM
Originally Posted by blazen_red_4x4
Welcome to the forum!
For starters, don't put it in 4wd on pavement and turn, that's asking for binding and breaking... basic unmodified 4wd isn't meant for pavement, it's meant for loose ground (off road use)
It sounds to me like you have either a front diff or axle issue.
Put the front of the truck in the air on jack stands. Start it and put it into 4wd, but leave it in park (chock the rear wheels and/or put on the parking break if you want to feel more safe). Doing this will engage and lock in the front diff. Now try to manually (by hand) rotate one of the front tires. This is going to get the gears in the diff and the axle shafts (while they've also got some angle at full suspension droop) moving. See if you can hear or feel any of the clunking or popping noise while rotating them. If not while the wheels are pointing strait, trying turning them left and right, still while it's up on jack stands, still while it's running, in park, in 4wd, and see what the results are.
IF there's no noise after doing this, my next guess would be some very worn suspension components, like ball joints or control arm bushings, but that noise won't usually go away like you're describing...
Once you can replicate the noise in a controlled environment, you can begin to track it down a little better at least.
I used this similar method to track down a bad wheel bearing on a 2 post lift :P
For starters, don't put it in 4wd on pavement and turn, that's asking for binding and breaking... basic unmodified 4wd isn't meant for pavement, it's meant for loose ground (off road use)
It sounds to me like you have either a front diff or axle issue.
Put the front of the truck in the air on jack stands. Start it and put it into 4wd, but leave it in park (chock the rear wheels and/or put on the parking break if you want to feel more safe). Doing this will engage and lock in the front diff. Now try to manually (by hand) rotate one of the front tires. This is going to get the gears in the diff and the axle shafts (while they've also got some angle at full suspension droop) moving. See if you can hear or feel any of the clunking or popping noise while rotating them. If not while the wheels are pointing strait, trying turning them left and right, still while it's up on jack stands, still while it's running, in park, in 4wd, and see what the results are.
IF there's no noise after doing this, my next guess would be some very worn suspension components, like ball joints or control arm bushings, but that noise won't usually go away like you're describing...
Once you can replicate the noise in a controlled environment, you can begin to track it down a little better at least.
I used this similar method to track down a bad wheel bearing on a 2 post lift :P
Yeah the only times I was in 4x4 on pavement was this winter in snowy conditions, I'm up in MN.
I'll jack the truck up and try that and see what I can find out, I had done some digging around to see if people had similar problems and had read that worn U joints or yes the front CV axel shaft might be the issue. Hopefully I can figure it out, thanks again!
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