Ok so I just tested the switch and everything looks fine to me.....Here is what I found:

• No buttons pushed - 9.10
• Auto4WD - 0.06
• 2High - 1.51
• 4High - 0.66
• 4Low - 2.34

I had my multimeter on 20K so that's why I don't have the last digit.

I was under my truck today and i did not see anything like that vacuum switch in the pic of the t-case you posted Kyle. I did however find and electrical connection with two wires, that was the only thing I could find that looked remotely like that vacuum switch. JP I think you may be right about this t-case not have a vac switch because I could not find one, but I did see a vac line going into the top of the case.

 

JP is probably correct on the transfer case switch. I was looking at an exploded view that showed there being one. I have not seen a NV236 transfer case in quite a while.

 

So I was out a little while ago and it feels like the 4wd is working but with some binding, the light still blinks. I really felt the binding while pulling in the driveway, the truck came to a complete stop while turning and I had to give it some gas, normally I would just cost up into the drive. I put it into park and switched back to 2H and the truck jerked forward.

 

The front diff is a "posi" so to speak. It will bind when engaged. It sounds like the axle is operating correctly.

I have a similar issue to yours. The lights blinks and if I set it to auto, it eventually switches back to 2WD. It does feel like it is working in 4WD hi and lo.

I am watching patiently and I will try a few thigs also. If I come up with something I will post back so you can try it.

 

A blinking light still means that things are not happening the way that the TCCM needs them to happen.

Just to clarify on the above post. The front diff is a standard open diff with a disconnect on the passenger side so as to reduce the drag when the vehicle is not in 4wd. The reason for the binding while turning is due to the lack of a differential in the transfer case.

 

Is there an order to what is actually supposed to happen when the button is pressed?

Mine feels like it is engaging, but the light is blinking. I will check tomorrow by raising the rear wheels off of the ground.

 

The encoder motor turns until the 4 different position sensors tell the TCCM that the sector shaft is in the appropriate position. If the information given by the encoder (4 position sensors) does not meet what the TCCM is looking for, the light blinks. If the sensors get out of whack (most common encoder motor failure), the TCCM will not be able to effectively put the sector shaft into the appropriate position or, rather, that the TCCM does not know that it has put it in the appropriate position.

You basically need to measure the encoder channels to see what is happening in yours.

 

Is there any documentation on which of the four encoder channels are on/off for each mode? That would help to debug this type of problem.

 

Kyle so your saying it might be my encoder going bad then? For all the info I have on this truck with the previous owner to my knowledge and his, he was the second owner, he has not replaced the encoder motor, it might be the original. Is there a way to bench test or test in any other way if the encoder is properly working?

 

Have a look through the documents I linked to from RSGear. The encoder is very similar between the NV233 non-auto transfer case and the NV236. It is permissible that the channels are similar as well. It gives you something to go on. Check out the NV233 specific documents for further information.

But start with the NV246 documents from the link above as they are very, very similar. Specifically pay attention to the diagnostic section in the NV246 articles. Much of the diagnostics that can be done on the auto4wd transfer cases have to be done using a scan tool.