2000 S-10 Blazer. It has the 3-button system: 2Hi, 4Hi, 4Lo.

99% of the time, it's always on 2Hi. We had to put it in 4Lo to get out of some snow; now it won't come out of it.

We tried getting out of 4Lo when in drive, neutral, reverse. When hitting 2Hi or 4Hi, it just blinks and the TCCM clicks. The TCCM was replaced and does the same thing.

We're looking at the vacuum actuator now; it looks like this:


The problem is, I didn't take it out myself. I was asked where that upper tube (in the picture, by the engraved numbers) is supposed to go. Does anyone know? Pictures would be nice if applicable.

Aside from this, is there anything else that I can check for? How are we to know/test that the vacuum actuator is actually faulty? Where do I go from here?

Thank you.

 

i had the same thing happen to me. It was the encoder motor. cost me $450

 

Details on the encoder motor? Part number? How to install it? How can I know for sure that's the problem?

 

i dont have much detail. i work at a dealership so i had one of the techs put it in for me. I dont think it would be too hard to install i just didnt want to have to drive it home in 4lo. It is located in front of the transfer case. Not sure on how to check it.

 

Thank you for your assistance. Truth be told, I'm personally not too good with these sort of things, but I'd like to do all I can before finally bringing it in to a professional.

 

A vacuum actuator should not prohibit the shift from 4LO to 2HI or 4HI.

Have you tried disconnecting the battery?

 

The battery is currently disconnected due to another issue; I don't believe it has been reconnected. If it's still an issue after reconnecting, where should I look to next?

 

Just replacing parts is sure to get the problem fixed eventually, but it will be expensive.

For the NV233, you can check the codes by following the details in the thread linked to below:
OBD2 Non-Automatic Transfer Case Diagnostics

You can also check out this thread as only the method for checking codes differs between the 1st gen and the 2nd gen:
NV233 transfer case / encoding motor switch

 

Thank you. However, unless I'm mistaken, I don't have a tool that'll give me the readouts.

 

If you do not have an auto4wd option, then you are mistaken. Since you did not mention having an auto4wd option, I assumed that you had the NV233 3-button transfer case for which the diagnostic procedure for checking the stored codes in the TCCM was linked to in the first link in my reply above. Read that post and your questions in that regard should be answered. Start there.