4wd not engaging

[vaTBguy]

I ended up in some some mud and rear tires began to spin. Tried 4 hi and lo and had nothing. No lights are on and a week ago I was wheeling with no problems. Disco perhaps? Thanks

[v7guy]

It's the most likely culprit, using the flow chart has identified the ailing part for me every time.

[vaTBguy]

Thanks Dave, after work tomorrow I will check it out. I just wanted the opinion of a more experienced member. I appreciate it.

[vaTBguy]

I took the tb into some fields behind my house and 4wd is working perfectly now. I haven't gone through the flow chart yet but does this still sound like a disco issue?

[v7guy]

Frequently, yes, but occasionally the transfer case.
Sometimes as the disconnect wears and the bearings are going the gears and collar will be skewed and won't slide over each other because they're not inline. As everything wallows around sometimes they'll occasionally line back up. Sometimes it's also just lack of lubrication in the disconnect and it just needs disassembled, cleaned and lubed.
With the transfer case sometimes the motor that presses the clutches together isn't cycling properly. Generally it's not intermittent though.

If everything is working again and you can't get it to not work again I'd probably disassemble the disconnect and lube it up if it's never been done before. If you have access to a welder a few guys have had luck welding the gears and collar permanently engaged. It's a cheap duplicate of the AWD sleeve and should in theory increase the life on the bearings in the disconnect.

[vaTBguy]

Thanks again. I will tear it down, clean, lube and see how it does and go from there.

[Trail X]

A generally good measure of the wear of your disconnect is to crawl under the truck and push up hard on the passenger side tripod joint housing. If it is pretty well held in place, its likely not worn too much, but if you can move it up and down more than 1/8", you can be pretty sure that you're going to need to replace at least a needle bearing or two.

[vaTBguy]

Could the fact that I was already stuck in soft mud before I tried to engage 4wd have anything to do with why it didn't engage? Last night when it did engage I was on solid ground.

[Trail X]

Possibly. It does help the disconnect gears to be turning to get it to engage. If you're stuck, the front end can be extra problematic because the front passenger tire and shaft won't be spinning. It still would point towards wear, and shouldn't just be explained away. You should check into it.

[vaTBguy]

I most definetly will, thanks alot

[v7guy]

viewtopic.php?f=26&t=2480

That video shows normal slop, when I replaced the bearing it turned out to be fine. Obviously it'll be a little different on the pass side.

[vaTBguy]

Thanks for the link. I just checked the movement of the tripot. At the disco there is about 1/16 and the transfer case side is tight. Hopefully it will be good until the weather warms up a little and I will service the disco. Also, tried 4wd after work today and all was fine.