2004 blazer 5-speed manual 4x4. My front diff. whines like a freight train going on the highway it will drop the rpms while i'm coasting down hills only on the highway after it is warmed up for a bit, and i'll tap the gas and goes back to normal. replaced the vacuum switch on the t-case because the ball was stuck and had fluid in the vacuum lines, check the actuator and cable and it is shifting in and out. the front diff. had sludge in it and I had 2 drain it a few times to clean it out and obviously now one of the seals/gaskets on it leaks, but i know that is not the problem, although it is one. I have corrosion on the wiring harness on my tccm connector, cleaned it and it still happens, but acts up a little differently after i cleaned them, they're still pretty corroded though. the actual module looks good after I took it apart. I am going to replace the female connectors with new ones and solder the wires as well as crimping them, and pop them back in place and then spraying some ignition sealer and battery terminal sealer on the back of it to avoid future corrosion and see if it fixes it. I know its a problem, but don't know if its THE problem, so if anyone could help that fixed this problem before let me know. I'm a little stuck if this doesn't work, or let me know if I'm on the right track, i've been working on chevys 13 some odd yrs., I can rebuild a motor and a transmission but I am havin some trouble with this. Im gonna fab up quick tool to pop all those odd *** female connectors out of the blue plastic harness plug and get to work. if anyone has ever fixed this problem let me know, it'd be greatly appreciated. I'm just hopin the front differential engaging fork isn't shot after this doing that for over a dozen times as far as I had it. Thanks guys in advance.

 

Did you read any of the threads in the Tech Article (DIY) section as mentioned in the other thread you had posted in? The clicking in the front axle is discussed along with the design of the front axle engagement.

Did you clean out the vacuum lines? Having fluid in them is not good. It doesn't allow vacuum to flow through the lines properly and can seriously gum up the HVAC system.

As far as the connector corrosion goes, you can clean the terminals with some contact cleaner and connecting/disconnecting them repeatedly. Then coat the connection with dielectric grease to protect.


Since double posting is against forum rules, I have removed your reply from the other thread. Lets try to keep things in one location.