Brand new to the forum, awesome site. I have a 2000 Blazer 4WD LS 2door and it's making a loud clunking and chunking noise when accelerating from a dead stop or turning. Does any one have any idea as to what it could be, the noise seems to coming from the transfer case. Also how can you find out which model number my tranfer case would be. Thanks for your time

 

You should have the 2-spd selectable (NP-233), there are three buttons on the dash - 2HI/4HI/4LO - if there is a 4AUTO button then you have the Automatic transfer case (NP-236) that usually comes in the upscale trailblazer and the Olds Bravada.

You could have a CV joint failing, but does the noise go away in 4wd??

If the noise happens when turning then you could have definately have a CV joint in the front half shafts going out to the wheels from the front differential..do you see any grease in coming out of the rubber boot near the front axle hub, sometimes these boots will tear and cause excessive wear to the joint and it will slip making a clunking noise under turning or 4x4 mode...

 

Thanks for the help, I checked the cv joints and there was no grease coming out and the boots were in good shape, no holes and or tears. Do you think that it could be a bad u joint?

 

Could be but they normaly don't make "noise when turning", this indicates front suspension parts or CV joints.

Jack up the front suspension and check the ball joints for wear, have a buddy put hands at 12 and 6 o'clock and try to move the tire in and out at the bottom. If there is noticable movement then the lower ball joint needs replacing. To check the upper put a lever under the tire and lift up and check movement at the upper ball joint the same theory applies, if you can see noticable movement I would have them replaced. Depending on your confidence level you can do the job yourself...

Also check for rubber bushings falling apart.

 

If you are unsure as to what is causing the noise I would advise having it checked by a shop. There are some shops that give free inspections. I'd rather even see you spend a few bucks on an accurate diagnosis than spend a lot of money replacing perfectly good parts.

Try the suggestions that 20Blazer00 has given you first.

 

I'd have a look at the front driveshaft. at the joint directly ahead of the transfer case.

Mark - I don't think the olds ever got the 2spd TC... I believe it was AWD (no low range) only.

 

Wondering if you could help? I have a 91 Bravada I hear loud cilicking and clanking from the transfer case when I put it in gear but the truck goes nowhere. This is a AWD so it is always in 4x4. Can I eliminate the transfer case and make this a 2wd? Any input would be great. Thanks.

 

~In response to kec70nova's posting...I would check if the loud clunking only occurred at a certain RPM. I know when my t-case was having fluid problems, it clunked around heavily but only at a low RPM. Roughly 1800-2000. I drained and refilled the fluid in the t-case, and the clunking stopped. I think that as the temperature increased with spring arriving the gear oil, with a long winter behind it, had dissapated and needed refilling.
~For the AWD bravada, I really don't know where to start because they had a specific Borg Warner T-case that was a little different than that in earlier model s-series trucks.