1998 Blazer 4x4
171,000 miles

So I am having an odd issue with my 4 wheel drive. It engages into 4 wheel hi no problem. But whenever I go back into 2 wheel the light flashes a few times and I can hear a click and notice my dash lights dim and then stays in 4 wheel hi. I checked vacuum and we do have it. I did notice some transfer fluid leaking at the 4 wheel vacuum switch but I don't think that would cause any of the problems. Plus I bypassed that switch and still couldn't go back into 2 wheel drive. The weird part is that sometimes it will go back into 2 wheel drive when I push the button and can't come up with a good reason why it does. Sometimes it takes days to finally get back into 2 wheel drive after repeatedly pushing the 2 wheel drive button. Any ideas? Let me also note that I can go back between 4hi and 4lo with no problems ever. It's just going back into 2 wheel that I have the problem.

thanks

 

Just wanted to leave an update. I replaced the vacuum switch on the transfer case and it did not fix my problem. Thanks

 

did you replace any lost fluid? I Cant really help you bc my blazer is permant 2WD being only RWD. Sometimems when the fluid is low, it wont work, my friend had a similar problem, its like when your a Qt low on tranny fluid, its shifts eratic and bad. Check it out and give it a shot if you havent replaced any lost fluid from it

 

Where do I add or replace the fluid? Is there somewhere on the transfer case? Thanks for the response.

 

thereshould be a fill hole on the transfer case, i think you have to pump the fluid into it. Im pretty sure whenyou lost fluid its not engaging properly now, check it out on the transfer case

 

There will be two plugs threaded into the back of the transfer case. The lowest one is the drain plug. The one about 4" or so higher is the fill plug. You out fluid into the transfer case through the fill port (where the fill plug threads in) until the fluid starts to leak out. The truck should be level for this so you do not under fill it.