Hi, I have a 2000 blazer and the 4wd doesn't sound right. When I engage the 4hi or 4lo it works but as i roll forward it makes a clunking sound coming from the front of the vehicle. I have not used the 4wd because I didn't want to do any more damage. We just got a ton of snow and I had to use it a couple of times for a second to get unstuck. I was wondering if maybe it is not engaging completely. I want to get this fixed so I can get around in this snow. Any suggestions?

 

My 99 had the same problem. took it to trans shop, the mechanic seemed to know what the problem was but didn't seem interested in fixing it. Best I could tell it had to do with the vacuum linkage from the switch causing it to not engage properly. He obviously did something because it works better now.

 

hi, I have a very similar problem with my 2000 blazer. Its fine in 2wd, sits at 70mph quite happy. But when trying to use 4wd hi or lo there is a clunking noise as you describe.. I have replaced the usual suspects first like shift motor, transfer case fluid, some failed vacuum pipes and the vacuum switch on bulkhead. None of these fixed the fault! I am going to remove front propshaft and drive car in 4wd to see. I am expecting to find a faulty U/J. I will let you know how I get on.
Hope this helps

 

i havnt had a chance to mess with it yet but thanks for the responses, i really hope its as simple as a vacuum problem

 

you never said if the noise was coming from one side more than the other. is it? does the noise seem the same or worse when making turns? how about sharp turns? (when @ lock)

you also never said if you were completely stopped when you egaged the front diff. were you?

@ audiboyV8: there are no u-joints in the front end, they're cv shafts. similar, but different.

 

I have removed propshaft and run in 4wd. No noises at all now! At least its not transfer case.
I have the prop off and the u/j at the front is fine no play or stiffness and the cv type joint closest to transfer case is also fine.
My next stop will be to remove front driveshafts and check cv joints.

I think confusion over cv joint & u/j is that i'm in uk, possibly we have different names for the same thing?

Blazers are a bit thin on the ground here and getting parts is difficult and time consuming.

Will keep posting as I find things and hope this helps others

 

It does seem worse when I turn the wheel in either direction, and i have engaged it stopped and moving.
I recently replaced the cv joints thinking before that since they were bad they could be causing the sound but it didnt change after i replaced them.
Oh and i didnt notice a difference from turning at full lock and regular turning.

 

Hi, How are you getting on with fixing your blazer?
Hope you have more luck than I'm having, I was able to confirm today that thanks to the USELESS Main Dealers for Chevrolet in the UK the transfer case is faulty ( not checking oil level at service time! ).
A new one is big money so I will be removing and rebuilding this one very soon.

 

man, that sucks! (guess you spoke too soon about your diagnosis)


actually, i should appoligize. i re-read your first post, and saw that you're from England, so the propshaft refrence made more sence. we call 'em driveshafts. and they do indeed have a u-joint @ the diff.

like i said, it really sucks that you got shafted by the service guys not doing their job correctly, which, unfortunately you can't prove.

this is a prime example of why i do all my own service/repairs.

i sure don't envy you non-North American owners. while it sure is sweet to have an uncommon DD, it's a hard kick in the nuts when something fails on them-especially when it's not your fault!

 

Got our first heavy snow fall here in Sydney, NS. Bought my 2001 blazer a year ago. Not one problem drives great. Never had a problem with the 4Hi used it many times before off road. I clicked the blazer into 4HI to get home in the snow the other night and the banging and noises coming out of it where definitely a cause for concern. I know it's most likely the transfer case, from what I can figure working around other vehicles and what I have read on here. I'm just wondering if anyone tell me what exactly has to be changed and how big of a job this is to do and how much $ this problem usually costs to fix. Any help/info would be greatly appreciated. e-mail nscc_grad08@hotmail.com