Problems with 2 wheel drive

[awhite0420]

Hey everybody i recently started having an issue with a grinding noise on the highway. Only in 2 wheel drive and when i switch to 4 wheel it stops. I searched everywhere and found a few articles and im pretty sure its the vacuum switch on the transfer case not allowing the 4 wheel to completely dissengage. so i pulled the switch and i thinkg the ball is stuck. i couldnt find anything about whether or not i should be able to move the ball back and forth or not. I cant budge it at all. I even tapped it with a hammer and it wont budge. Also if this is the problem should i take apart the front diff and check out the half shaft side gear and sprocket? Any advice would be appreciated. thanks

heres a video i found and a few pics of my switch

http://www.youtube.com/watch?v=R4AnKG3aOIw

[killian96ss]

Did you already read this? Revised transfercase switch

They are known to fail sometimes resulting in HVAC damage because of the fluid contamination. Yours appears to be seized which I have seen on older models. Get a new updated switch in there before you end up with more problems!

Steve

[awhite0420]

Yeah I skimmed through that one killian, A lot of warranty talk and mine doesnt fall into that catagory lol but it definitely helped me locate it. When i took it out i did inspect the lines for atf fluid and didnt see any signs of it. but the switch didnt have an o ring on it which i thought was strange. Anything else i should look for in terms of an HVAC issue? I drove it for about 15 miles with it making the noise on and off. Just enough to get it home and havent driven it since. Should i take apart the diff and inspect the half shaft and coupler gears for damage? I already have the axles out and got the new ones in today so before i put those in id like to check the diff if thats necessary. My buddy ordered the revised vacuum switch for me yesterday i should have it tomorrow or monday

[Indigo04]

I replaced the switch in my 04 as well, stuck the same way. I got a new one at autozone for like $18.

[killian96ss]

I would just put a new switch in, check for correct 4wd operation, and listen to see if those noises went away. If the noises persist or the 4wd system isn't working properly, then you know either something was damaged by the seized up switch or you had other problems all along. I wouldn't tear into the diff unless you know for sure something is wrong. I don't remember if there was an o-ring or a small flat gasket on the switch, but there should be something there to seal to the transfer case.

Steve

[awhite0420]

well i took the axle shaft and tube apart from the diff and man was i glad i decided to check it out because i found this.



This is such a common problem but i only see people replacing the vacuum switch and never replacing the gear that was grinding. So needless to say I havent been able to find a part number. If anyone can help that would be awesome cause i cant find it lol. every where i see this its called a Front Drive Axle clutch gear but in the diagram its called something else.

[awhite0420]

im going to post this in the appropriate thread also just figured id update here also

[killian96ss]

Do you have a GM dealer near you? Even if you don't buy the parts from them you can at least get the correct part number.

Steve

[awhite0420]

i got it lol i tried the dealer first. the genius at the parts counter couldnt find it. called a different dealer yesterday and had to special order it. thanks