My 4wd quit working too!

[turbodudey2]

Well the 4wd quit today. Haven't figured out why yet. I read through a couple threads from other people who's 4wd quit but they all were problems with the ADD. Mine on the other hand is not even engaging the front propeller shaft (in 4H or 4L), and the ADD won't try to do anything until the propeller shaft is engaged. (so hopefully the ADD is fine)

I haven't looked at the FSM yet (it's at home), but it looks like there are two separate switches on the transfer case that both have to work to engage the front drive shaft. I checked the 4wd push button on the shifter itself, and it seems to be working... maybe. It was 16V open and 0.2V closed. So clearly it is grounded when engaged, but maybe 0.2V is not quite grounded enough...

Ideas?

 

[quicksilvr]

That sucks.

What was the situation in which you were attempting to engage 4wd and realized it was not working?

 

[NickF]

This is why I'm glad I don't have a "real" limited. I like my 4wd shifter, thats not push button. :lookout:

Anyway, .02v is so far off of 16v that there's no way that is the problem. I say try and flush it out, the old fluid could have just gummed up and made it hard to engage.

 

[turbodudey2]

What was the situation in which you were attempting to engage 4wd and realized it was not working?

I was backing up a steep hill with one rear wheel on gravel. I park in this spot quite often, so I've gotten used to just clicking 4wd on and backing right up. This time when I hit the button... nothing happened. The indicator light didn't come on, and I didn't hear the ADD click. It just didn't even try to do anything.

I just goosed it to get out of the spot (I wasn't actually stuck), and then tried several more times to engage 4wd while driving around at various speeds or just in neutral. It just won't even try to go in. I checked 4L too, and the front drive shaft is still spins free by hand. That's why I was thinking the switches on the t-case were suspect.

I say try and flush it out, the old fluid could have just gummed up and made it hard to engage.

It has brand new fluid in the t-case and diffs. I just changed them all less than a thousand miles ago. Even the old fluid that came out wasn't that bad.

 

[turbodudey2]

fixed

My first thought turned out to be right. It was the push button switch. It just wasn't grounding quite well enough.

I was messing with it some more this evening, and I just double checked the push button, because my initial test showed that it wasn't quite grounding. I'd tested it with the ignition on, so I was looking at the voltage, but the FSM said just to check continuity. It was about 600 ohms closed - yikes!

Cleaned, reassembled... all better.

I like 4wd.

 

[quicksilvr]

I had a feeling you'd get it fixed quick.

Did you see my thread on Jessi's truck yet?