My transfer case will only pull vacuum to the hubs when floor shifter is in between 4 low and 4 high. as soon as the dash light comes on for low or high it looses vacuum. Is there a switch that tells it to pull vacuum? Does anyone out there have a good breakdown of the transfer case?
I don't think I understand what you are saying....When you put your truck in 4 wheel drive the hubs should loose vacuum to allow the hubs to lock into place. When you put it back in 2 wheel drive the hubs should have vacuum to pull the hubs back and disangauge the hubs. In 2 wheel drive your hubs will always have vacuum.