4x4 Trouble

[MikeStoke]

Hi all, I am having problems with my 4 x 4 in the automatic setting. When I throw the switch sometimes it will engage and sometimes it wont. I read somewhere if your having problems with a vacuum leak to throw your heater on and engage your 4 x 4 and if it switches to defrost that you have a leak. My question is how do you know if it is my front axle seals or the vacuum pump? I am getting a light on the dash but it is not engaging in less I get out and throw the hubs into manual position. Any help is greatly appreciated. The dealer wants around $100.00 to test it. But you all know how tight $$$ is this time of the year!! Thanks in advance.....Mike

 

[Skandocious]

Play with your heater/ac on different settings while loading up the engine on a steep hill. Mine often changes from Vent to Floor or Defrost when I bog the engine on a hill. If yours does the same then it's your vacuum pump. If you're not having vacuum problems anywhere else then the problem is most likely at the hubs.

EDIT: Crap Brad just called me and made me realize. Engine load ain't gonna do crap with a vacuum pump Scratch what I said above-- that test won't work on a diesel. But basically if your vac pump isn't working then you shouldn't have heater controls at all. I'm thinking your problem is near the hubs (either the seals or the lines).

 

[Bloodhound]

These trucks are bad about the vaccum lines going to the hubs cracking. I actually need to trouble shoot mine. it is probably something simple like a vaccume line. i have seen posts about how you can check it with a hand vaccum pump to help trouble shoot it.

 

[MikeStoke]

Thanks for the replys, I have found out that its the hub seals. So when it warms up I will be hitting them. Thanks again Mike