Newbie here looking for alittle direction, but first I have a question that may make thing make sense.

Is there a "transfercase vacuum switch" on the transfer case of an autotrack system ( 4 buttons auto 4wd, 4hi, 4lo, 2 hi) or not. I have found conflicting information on the internet and the Haynes manual does not differentiate between the systems in thier manual. I have looked but it is not there or I am not looking hard enough. A definitive answer from somebody with more experience than me would be appreciated.

 

There is no vacuum switch on the NP236 transfer case which is the name of the Auto4wd transfer cases.

 

Thanks for the answer. That means I am understanding the system correctly.

Now it off to find out why the service 4wheel drive light comes on after a few miles of driving. Any ideas? It will not engage the 4 wheel drive but I have got it to go into 4 lo. I have cleaned the contacts on the tccm. I have traced the vacuum lines and have not found any leaks. So I am now looking at the encoder motor or the sensor swiches.

 

The intial problem was the 4 button dash switch. It worked for a few days now it will not go into 2 wheel drive it keeps going into 4 hi. it will flash the 2 hi button and then revert back to 4 hi. Anybody have any suggestions for me as to what is going on now.

 

Did you replace the dash switch? If not, you can test the one you have by measuring the resistance resulting from each button push. THIS POST will show you what you are looking for. Others can be found by searching for "NV236".

 

Thanks Swartlkk. I have not tested the switch but I did put a new one in. It worked or a couple of days then the Service 4 wheel drive light came on again. I found a used tccm for a cheap enough price to try it. That seems to have it fixed. I am not sure if it the light might have been due to a poor contection as there was some corrosion on the unit that came out. I am just happy to have it working as the snow is on the ground here. Now I am off to do battle with the front wheel bearings.

 

You will want to clean those terminals on the connections to the TCCM with some contact cleaner and scrub them up as best as you can or the corrosion will come back and cause the same problems. Use some dielectric grease in the connector to help stave off the problems all together. The key is to get things clean.

 

Thanks Thats exactly what I did. I also hot glued the back side of the wires into the conectors as they seemed to be working their way out. I had also checked the vacuum system under the hood from the solenoid to the acuator for the front axle. I also had the encoder motor off and cleaned the corrosion from around the motor on the transfer case. ( again I figure a little dielectric grease would not hurt.)
The 4 wheel drive works like new and it is no longer a scary unknown system. Repair cost about $120.00 in good used parts and a couple of cases of refreshment.

As I commented in another thread where someone had similar 4 wheel drive issues the cost of the dealer parts in Canada seems to be way out to lunch. The TCCM I was quoted $950.00 the Dash switch was around $300.00 was to scared to ask about the encoder motor.

Went cheap got lucky and had some great online help. again thanks