Just got a 97 blazer, old owner put in a used eng/tranny about 1 1/2 yr ago, and 4wd stoped working about the same time. I have found and repaired: vac supply hoses off, damaged, and open tees, vac hose off acuator, dash switch broken. I'm to the point the button engages/transfer case, and in 4wd I get good vac to the hose for the acuator, when switched to 2wd the supply of vac stops, but it holds vac untill I open the hose to release it. I was worried about connecting the hose, and havn't touched 4wd with it on. There is a capped off tee in the hose going back forward from the vac switch on the transfer case, but I can't find where it should go. Is there an elect switch to release the vac? How much damage would it do if drove it with the ft engaged and the trasfer case dis-engaged? They are talking snow again, and where I like it takes 4wd to get in/out.
Thanks.
Steve

 

Update. Looks like that part is fixed? I jacked up a ft wheel, and turned it by hand. It turned in 2wd, engaged in 4wd, and could turn it again after pushing 2wd again. I couldn't find where the hose is supose to go but looks like it's working.