Originally Posted by supermario28

if the vacuum switch was bad what would it do to my car? would i see smoke? or a leak?

Originally Posted by AintQik

I just fixed mine last weekend. First pull the fill plug out of the transfer case and see how much extra fluid is in the transfer case. If there is any, you need to replace the seal before you do anything else. The seal is $11, dont buy the cheap one. You can replace the seal without dropping the case. (My Blazer is a 01 ZR2). Remove the shafts, take out the tranny mount and cross member. Drop the tranny down until the trasnfer case is resting on the torsion bar cross member (as low as it will go). Remove the encoder harness and the other plug. Remove the bolts that hold the transfer case to the the tranny. Leave the adaptor plate on the transmission. The case is around 60 pounds. It probably will not come out but don't get your head smashed. Push the case back as far as you can get it and twist the front toward the passenger side. You will see the seal. the seal retainer is held on by 4 bolts. They have sealant on them so be prepared to fight them the whole way out. The retainer is sealed to the case but there is a hole/slot in the side to get a small prybar in there. I'd say its at like 10 o'clock. Pop it off rejoice. It will clear the transmission if you buggy lug the case around. Replace the seal and put it back together. My tranny friend, well wait let me rephrase that, my friend that works in a transmission shop tells me the best sealant to use is Ultra Gray. There is no paper gasket available to replace the one between the transfer case and the adaptor. Use the Ultra Gray there too. Just get up in there and make sure both surfaces are clean and remember its aluminum so don't get all nuts up there with a razor. Put it back together easy squeezy.

Now you got the leak fixed, replace the vacuum switch. While the plug is off spray compressed air down from the feed line over by the brake booster. Clean it with simple greem or something or replace the line. Then take your dash off and your AC panel off. The blend door dealio had a vacuum switch that needs to come off and be cleaned. On mine, the switch itself had gone bad from the fluid. I had to replace, I could not get it to stop hissing. New one fixed it. You may or may not have lost one of the blend door actuators. Check em and replace. If they are good try and clean em. Tranny fluid will kill em over time. Next take the battery out and check the 4x4 actuator under the tray. Mive still worked but I can feel its slimey inside like there is some fluid in there. Its not going to last much longer, but its easy to swap. If yours is holding vacuum its your call whether or not to change it.