88 Wrangler Lost the 4 wheel Drive today

While plowing I lost the 4 wheel drive ? I have the type that is activated by vacuum. I thought I heard a clunk when I park it last night , I was thinking it was the plow when I lowered it. But now I don't know what it was. I went out this morning to clear the driveway and the 4 wheel drive wasn't working. I rarely take it out of 4 wheel drive because I just use it to plow my property in the winter. Is there a way to get it engage and lock it in there? I tried low gear on the transfer case but still the same problem. Any advise would be appreciated.

While plowing I lost the 4 wheel drive ? I have the type that is activated by vacuum. I thought I heard a clunk when I park it last night , I was thinking it was the plow when I lowered it. But now I don't know what it was. I went out this morning to clear the driveway and the 4 wheel drive wasn't working. I rarely take it out of 4 wheel drive because I just use it to plow my property in the winter. Is there a way to get it engage and lock it in there? I tried low gear on the transfer case but still the same problem. Any advise would be appreciated.

Theres a product called a Posi-Loc that replaces vacuum actuator with a mechanical, cable operated actuator, so you can engage and disengage the front axle as you need to. I am setting my YJ up to plow and I installed the Posi-Loc so I can disengage it and make tighter turns while in low range without stressing the front axle ujoints and shafts too much.
For a quick fix, you can crawl under and trace the vacuum lines back to the transfer case and make sure they are connected and intact or you can take the actuator cover off, you will see how the fork and collar slide back and forth, and install some spacers and washers to keep it engaged.

Thanks for your reply.... I checked the vacuum lines they look ok. I suspect the diaphram went? Is the posilock system you described expensive?

Thanks for your reply.... I checked the vacuum lines they look ok. I suspect the diaphram went? Is the posilock system you described expensive?

The Posi-Loc is about $160.

EDIT: Here it is for $199 but I think you can beat that price if you shop around.
http://www.quadratec.com/products/product_search.php?kw=posi+loc

Ray, Thanks for the info... Good news is that I just broke a U Joint and that will be a cheap fix for now.