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· Registered
2004 chevy trailblazer_ls_ext
788 Posts
Sounds like the inside of the CV axle is worn out. I can't think of anything inside the disconnect that would clunk like that.
If you pull the CV axle, it would be a good idea to remove the disconnect, and disassemble, clean, and re-grease it.
The disconnect is bolted to the oil pan with 4 bolts. I'm going to assume you already have the vehicle up on jack-stands. Get underneath and remove the 4 bolts holding the plastic "skid plate" on. Once that's remove you have clear access to the rear of the disconnect.
The disconnect will be corrosion bonded to the oil pan. If you try and just pry it there is a high likelihood that you will break the disconnect and leave the back half stuck in the oil pan.
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What you want to do is use a plastic or rubber hammer and tap the bottom of the disconnect, on one side or the other, straight up towards the hood of the car, not out towards the fender. You won't be able to go very far with it, maybe 1/2" or so. Then tap the other side in the same manner. Do this 2-3 times. What you are doing is breaking the corrosion bond between the disconnect and the oil pan.
NOW tap the back of the disconnect out towards the fender, just a little bit. Then tap on the front and drive it back towards the oil pan. Repeat this process, going a little farther each time, and the disconnect should come out without any damage.
Here's a good article on rebuilding or servicing the disconnect. If you find damaged parts, use the part number in the article to find replacements. They are still available.

When I replaced mine this past fall, I knew I was going to be replacing the CV axle, so I just used an angle grinder with a cut-off wheel and cut the axle shaft in half. Then I used a bench vise, a steel drift punch, and a 3 lb. sledge hammer and drove the stub out of the disconnect. If your axle won't come out of the disconnect, that may be what you need to do.

· Registered
12 Posts
Discussion Starter · #22 ·
So the left side don't have the same thing as the right? I guess i'll try the low speed test maybe tomorrow, l watch a few videos to remove it and seems it could be a pain getting the axle back in...IDK
It's been a few days but finally got my hands on the vehicle, l test drove it doing what you said to try and there was no strange sounds/grinding or anything else. Is it possible when l changed the oil, which was disgustingly gross, that the new 75X90 oil helped? The 4WH works (l hear the actuator doing it's thing) and shifting to 2W back to 4WH numerous times went flawless!

· Premium Member
'05 TB 4.2 EXT
6,208 Posts

l am trying to figure out how to upload a video of the clanking which is not the gravely sound, it doesn’t sound good
That's normal --- there has to be some clearance in there or things would not like to spin and change angularity at the same time.

You might be hearing one or any number of the following things here ..... but it depends if you are Sponge Bob or Superman when you are twisting that shaft.......

The Side gears in the differential - kinda normal
The CV trochoid should be a little quieter, but it does clack a bit
The splines in the side gears-to-the-output shaft
The spider gears inside the differential carrier assy.
The spider retainer pin --- NOT NORMAL! Requires investigation NOW!

FTR --- there is always some "slop" in the contact patches on the drive/v/coast side of the ring & pinion. This is the end result of all the other aspects of the gearface contact setting being normal.

There are not too many other things that go "bump" in that side of the driveline --- but someone might come up with another.
........... AND remember that these kindsa sounds telegraph - in that they might be in the tail lights but you hear it in the front drivetrain.

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