A few days ago, I slid into a deep mud pit trying to drive around it and I got stuck. Turned the 4wd drive on and tried to get out but I couldn't and ended up bottoming out. The 4wd was working. I let it sit overnight because it was getting late in the day and came back the next day. Tried to pull it out with a tractor and couldn't. Put it back in 4wd and it wouldn't work. An excavator and a dump truck later, I got it out. I haven't really messed around much with trying to engage it. I'm afraid I will mess something up. I don't know what it could be. I'm sure it has to do something with mud or water getting in somewhere. It's an 04 fx4 by the way. Just hit me with some suggestions and I'll go test them out.

 

What makes you say that the 4wd wasn't working?

I'm not sure how familiar you are with axle differentials, but just because you have 4wd engaged, doesn't mean all four wheels will spin. Google for "open" differential, then read about limited slip ("posi-traction") and locking differentials.

The easiest way to test 4wd is to put the back wheels on something slippery in 2wd - gravel, mud (not deep), dirt, etc. Accelerate hard. Then repeat in 4wd. If you don't notice a major difference, you're not in 4wd.

 

Here's something new. I found this hanging on the right side. I think it may be the vacuum hose?? I will test the 4wd tomorrow.

 

I'm not sure off the top of my head what that is, but it appears to plug in at the end of the CV boot based on your picture.

 

Clean it off, place the hose back on the nipples, and put a zip tie around it. Then see where you are.

 

that is your vacuum and vent line to your IWE which you can see in the picture ... plug it back in and you should be good to go... it may have got pulled off when you were attempting to get your truck out..

 

That vacuum hose being disconnected wing prevent you from getting into 4WD, but the resulting low vacuum could cause the other side to grind.

 

yes I did hear grinding also when I was trying to use the 4wd after I let it sit overnight. I just flipped the 4wd switch earlier and I heard the usual clicking noises, so I think it might be working.

 

Did you put the vacuum hose back on? You can see the nipples where it attaches to the IWE in your pic.

 

yes I put it back on