I have the same problem. I haven't got under to see if the lines are leaking but would the heater controls still work if I had a vacuum leak?

 

I am not sure but my gut would tell me that there is enough vacum from the engine to still make the heater controls work. In my situation I had lots of vacum but a plugged line and also the shift motor was corroded and would not operate freely. Pull the lines off the vacum motor and see if you have vacum there, if not work your way back to the transmission and check there, etc. There is a picture of the front axle in an earlier post in this thread.

 

Do yourself a favor..

Posi Lock it, and forget it... Save yourself the headache and heartache and do it... here is a pic of my final instalation. It is the best thing u can get for your ride if u use the 4wd...., trust me..... Im a college kid on budget and wouldnt spend 200 dollars just like that...

For more refrence, please look at the following thread and check out the pic for what it looks like installed..

https://www.dieseltruckresource.com/...ight=Posi+Lock

https://www.dieseltruckresource.com/...cat=500&page=1

Thanks!!

Tx

 

I have to also suggest the Posi-lok system. Works great and I know it's in 4x4 when I need it.