I have an 02 Chevy Blazer 2WD 4.3L V6 Manual. Just yesterday I began hearing a loud clunking noise that I can feel through the floor board. The noise only happens when I begin accellerating from a stop - only one clunk. If I ease off the line, slowly accellerating, I can prevent the noise most times. But it doesn't sound good.
Time for an inspection. Sorry I can't be better help over a computer, but this should be checked by someone who can see it and tug on various parts. Blazers are known for two common problems but I'm pretty sure they both only apply to the 4wd versions. One is ball joints. These vehicles eat them for lunch and replacements are needed every 50,000 to 80,000 miles. The thing is though they won't usually make just one single clunk, ... Usually. That's why they should be checked.
The second thing is the rubber mounts for the cross member that the torsion bars are attached to under the seats. Usually they will rattle over bumps but they have been know to make one clunk when you start out. This won't apply if you have coil springs on front.
January, 19, 2011 AT 9:25 PM
Thanks - I'm thinking more in the direction of a tranny mount, since it only does it when the gear is engaged and only when the truck first starts moving. Not when I turn or stop.
January, 20, 2011 AT 4:59 AM
The typical symptom for the rear transmission mount is for it to shift position each time you hit the gas and put torque on it, even when the truck is already moving. If you have a helper you can trust to not drive over you, you can peek underneath at the transmission mount and the cross member mounts to see if they lift up when the transmission is shifted between drive and reverse and when doing a gentle brake stand.
August, 3, 2012 AT 12:46 AM
I've got the exact same problem as you 02ChevyBlazer! Except I have a 2000 Blazer 2WD 4.3L V6 Automatic Trans. I hear and feel a cluck from front end only one time when I first accellerate. Wont do it whjile driving. Will only occur again if I let it sit for 10-20 min. Did you find the source of the noise? I've had no luck and neither has any mechanics.