Six months ago the Blazer would not go into 4WD. I was getting a continuous vacuum to the front vacuum module. In fact it pulled the cable out of the module.

I replaced the three position switch module at that time. It fixed the issue and now only gets vacuum to the module when selected in 4WD. As I mentioned today the vacuum leak was preventing the front axle from engaging. It seems to be working correctly now.

So if I understand you correctly if there is a bad seal ATF is leaking into the transfer case and could be over full. I will remove the fill plug and see. That could be a bummer...

Unfortunately it did look like ATF fluid.

Is it me or do the 2nd generation Blazers break down a lot. 170,000 miles. My 89 4WD ranger is going on 250,000 miles and has been rock solid. All original.

JM

 

What is the white plastic tee. Filter?

 

One more thing I wanted to mention. When I replaced the three position vacuum switch no oil came from the transfer case.

 

The tee is a one-way valve that preserves the vacuum in the system when the engine is underload and cannot supply much vacuum. That is why a vacuum reservoir is part of the system.

You can find the reservoir's location in the diagrams at the links I posted.

 

I don't have much experience with any other trucks, but i've come to the conclusion that all GMs built up to the early 2000s can only be trusted for about 15 years before an owner will need to start regularly fixing things. Later vehicles might be worse.

For comparison, the vacuum hoses on my 82 Prelude, of which there are very many more, have never leaked whereas the ones on our Blazers often start leaking about the 15-20 year mark.

i've been thinking about getting a 10 y.o. 4Runner but their prices are outrageoua. Furthermore, to me they don't offer that much of an upgrade from what my Blazer can do.

Then there is that I've addressed the big issues with my truck that could make me want to get rid of it.

Finnally as an old Gen Xer, I dispise screens in cars and am motivated to keep my Blazer on the road, if for no other reason than out of spite. LOL

 

replaced 4wd actuator on my '96. replacement part had no return spring behind diaphragm not allowing 4wd disengagement. received replacement part and it was the same. brand is ROSTRA pt# ROS 73-0013 (rock auto) apparently that is the way that company makes them. don't know how anyone can use them like that. had a part store check DORMAN #600-102 and the sales guy said it had the spring. going to try one.
don't anticipate any issues. i'll update when i get the repair completed

 

I see the reservoir in your diagram. Very helpful. Since the existing line is capped off and not going into the reservoir I would assume there might be a nipple to plug it into or do I need to remove the inside wheel well to access the reservoir.

 

There should be a nipple on the vacuum reservoir. It is super annoying to get the hose on to it. It helps to first locate it with a mirror and flashlight to confirm that it is intact. Then stick your hand in there to feel for where you saw the nipple to be. Finally then you will know where to connect the hose.

This view is looking towards the outward direction from the rear end of the driver's side of the engine compartment. The reservoir is the black plastic part with the yellow diagonal stripes and the vacuum hose starts from the the middle of the right side of the picture and has the blue stripe on it.

 

Christine thank you for taking the time to lay this out. I found the nipple reassessed in the reservoir. Took me a while. I ended up loosening the abs system to gain a little more access.

The oil still concerns me. The transmission was almost a quart low. When I have time next week I will check the quantity of the transfer case.

JM.