Something wrong with auto 4x4, need advice...

[Wisco]

Hey guys, I'm not a real gear head and I kick myself for not knowing more, but I need your help...

The other day I notice that a dark color liquid was dripping off the truck in this location (see picture). It was not much and it stopped shortly after I noticed.

That night I drove during a snow storm. I turned the the knob to 4x4 high and with my foot off the gas, it felt like the 4x4 kicked in. Soon there after I got to a 25mph hill and clearly the 4x4 was not working. I got out, turned my manual hubs to lock, and the 4x4 worked great. This also clearly meant that the 4x4 knob wasn't working.

Any and all help would be great!




Sent from my iPhone using AutoGuide.com App

[gblauf]

The leak is probably an axle seal, but should not cause your problem, but get it fixed. The 4wd is vacuum operated by a vacuum pump on the pass inner fender. Notice the vacuum line in your picture above your leak. When the hubs are in the auto position, the vacuum kicks the 4wd on and off. When you lock the hubs the 4wd is engaged permantley at the axle. Your front axles will now spin with the wheels weather you put the transfer case in 4wd or not. Sounds like you may have a vacuum leak in those lines. I hope i didnt confuse you!

[Wisco]

Originally Posted by gblauf

The leak is probably an axle seal, but should not cause your problem, but get it fixed. The 4wd is vacuum operated by a vacuum pump on the pass inner fender. Notice the vacuum line in your picture above your leak. When the hubs are in the auto position, the vacuum kicks the 4wd on and off. When you lock the hubs the 4wd is engaged permantley at the axle. Your front axles will now spin with the wheels weather you put the transfer case in 4wd or not. Sounds like you may have a vacuum leak in those lines. I hope i didnt confuse you!

No that's all good stuff! Thank you. I actually have to go 1000 miles tomorrow back home from CO. Could I be looking at some problems with that axle seal?

[Tuscany]

If you have a leak there it is probably either a leaking axle seal or hub seal. Either one can keep the vacuum from building up enough causing the auto 4x4 not to engage.

[Wisco]

Originally Posted by Tuscany

If you have a leak there it is probably either a leaking axle seal or hub seal. Either one can keep the vacuum from building up enough causing the auto 4x4 not to engage.

Thank you! It's a lot easier to approach the mechanic if I have a slight idea of what's going on!

[Wisco]

Originally Posted by Wisco

Thank you! It's a lot easier to approach the mechanic if I have a slight idea of what's going on!

Could either of these have something to do with my 6" lift and 35s?


Sent from my iPhone using AutoGuide.com App

[twoicebergs]

Probably not, unless you go wheeling in water. The main seal is at the differential. The outer seal is more for keeping dust and dirt out. The leak could be diff oil or maybe just dirty run-off water. If it was not much oil, it may not require any work; it could have been sitting there for a long time waiting for you to lower the wheel to drain it. Only you would know what it was and how much.

[ZMANN]

Like mentioned above that oil is from a leaky inner seal or just water build up
and has nothing to do with the Vacuum side

that is all in the knuckle on the other side .

Your esof switch is working fine if the transfer case is locking in ,, whats not working is your Auto hubs ,, this is due to a bad solenoid or /seal/locking hub issue /vac line etc


the 4x4 dash light has no way of knowing if the hubs lock only if the transfer case motor moved to the expected position


you should be fine for a trip because that seal is so high the pumpkin will still have oil ,, u may want to overfill to be safe


also check the dif vent for blockage those can fors oil out of a good seal when plugged

[Wisco]

Truck is back from the shop...

First issue, the mechanism that creates the vacuum was not creating a vacuum at all. It had failed some time ago. Second issue, they put a vacuum on each hub seal and found that they were leaking.

So they put new hubs on and a new mechanism. Problem solved. I appreciate all your help guys!


Sent from my iPhone using AutoGuide.com App