I haven't ever needed help with my '94, only because I've never had any trouble out of it. Long story short, my bro threw a rod. I just got finished with the engine install 3 days ago and now the 4x4 won't engage. We hooked everything up the way it came off. So I ask you, the humble blazer forum community, what should I do from here? Details: '94, 4 door, 4x4, auto. Won't even try to go into 4 high in any gear but neutral and then all it'll do is TRY, you can hear the xfer case making the right noises but it never engages the front axle. Won't go into 4 low but rather, 2 low and that shouldn't even be possible without a major problem here. I checked all vacuums but I can check again just to be sure. The xfer case doesn't seem to be a part of the problem so I've eliminated it to the front axle. Anyone had similar problem? I searched the forums and the internet in general but my problem seems unique.

Oh and I've got tons of good parts off of that old engine if anyone needs them and is in my area. I've been helped here tons so I'd be glad to help back.

 

oh man, I wish I could help with this, these 4x4 systems can be a pita, hopefully someone can help you.

 

This is most likely a vacuum issue. Out of the back of the motor is a short vac line that runs to a 4-way splitter. One of those runs to the front diff. The t-case will still switch without it hooked up, but you will get the EXACT symptoms you describe. My 94 did this to me on the trail, and I was able to find the vac line disconnected and repair the issue. 2-Low is fun for making mud fly though

If everything looks good, remove the battery and it's mount to get to the front diff actuator. Disconnect the vac line there, and start the car. Put the car in 4x4 and see if you get vac at the line. If you do, bad actuator. If you don't, that vac line is not connected someplace and you will need to trace it back.

 

The 4-way split should be just to the passenger side of the distributor.

 

Mine had the same problem when I bought it. It was the vac line to the actuator under the battery

 

Yea while I was waiting on a response I was just checking back there and noticed 2 screws plugging 2 separate vac lines so I'll look into that in the morning, I have to work tonight but I'll report back ASAP. Thanks a lot!

 

Found one of em, it was the cruise control.

 

Those 2 were cruise control. Although I has a buddy press the 4x4 switch while I looked under the battery tray and the cable was not moving any but it's supposed to, right? From the acuator the cable is supposed to move like 3/4 inch I think.

 

yes. the actuator is supposed to move a noticeable amount. There shouldn't be 2 for cruise. One of them is cruise, one of them is probably your actuator for the front diff. If I recall correctly, it runs down from the motor to the t-case. Then it comes out of the t-case and towards the front diff. Again I would check if there is vacuum on the line, just in case the diff/actuator is just stuck. This will tell you where to go next.

If there is no vac, try tracing it to the t-case. See if you have vacuum going into the t-case switch (it's a strange ball thing with three vac lines if I recall correctly). Then see if you get vac out when the truck is switched to 4x4.

 

If the 4x4 engaged before the engine swap, unless you tore the actuator boot up taking the battery out, I doubt it would be a bad actuator. I think what we got here is one of two things, bad transfer case switch, or putting vacuum lines in the wrong places on that switch. The switch is located on the drivers side of the transfer case towards the top. It should have 3 lines connected to it. Here is a diagram of which vacuum lines go where on the transfer case switch. The lil black dot indicating the finger prong at the top of the switch. Good luck with it. The 4 way split also has a check valve in it. Allows air to go only one way. Make sure that is proper. At least, my 89 has that.