Hey new guy here. Truck is a '99 4x4 4.0 w/ 8.8" 4.10s and had it almost a year now and have used the 4x4 high and low before (about 4 months ago). Long story short, 4x4 doesn't engage. I've researched all over this site and others about common problems with the crappy PVH hubs. I took the hubs apart today and cleaned them out, one was filled with what looked like mud and grease and the other was spotless. 4x4 still no good, so the vacuum system is probably shot. Heres my plan, I'm gonna go into the hubs and manually lock them up and re-test the 4x4. If that works I'm going to buy the Rugged Ridge manual locks so I can lock and unlock the hubs without taking apart the stock hub.

Next; while I wait to diagnose the hub issue I have an actual question I couldn't find answered in the forums before. While I'm driving down the road, under 30mph, and I flip the 4x4 **** to 4hi there is a tapping/rattling coming from somewhere under the cab that matches the speed of the truck. When I come to a fully stop there is a slight clunk but still no 4wd. Any ideas about what that could be?

 

That noise is exactly what my truck did when the pvh hubs were broken. It's like the hubs were trying to engage but couldn't. I got the new manual hubs and that eliminated the noise.

 

Ok I'm relieved to hear that it's not my tcase slipping teeth or worse. Thanks a lot for the reply. Did you put the Rugged Ridge manual locks on your truck to fix it? I'm assuming so since they are the only direct replacement on the market for our trucks

 

Not to fix the noise particularly. It's just my 4wd had quit working and I had already had it fixed by ford a year earlier. I decided to go with the hubs instead of paying ford to fix it only for it to break again. The rugged ridge manual locking hubs have been working flawlessly since I put them in.

 

Try to find a vacuum leak, my 99 did this on a beach and got it home and found broken line

 

Ok thanks blitzy. Scott, I've tried to locate with a quick once over of the lines from the hubs by following them as far back as I could from the wheel well although I think I would rather hook up the manual hubs and just have piece of mind that they're locked up when I need them. Even if I have to get out of the cab into the freezing snow or mud haha

 

I'm just going to leave my hubs locked all winter and unlocked in the summer. Then I don't have to deal with the hassle.

 

Yea I'm probably just gonna keep an eye on the weather all winter and lock them whenever it snows. I'm a cheapskate so I don't wanna lose the 1-3 mpg unless I must haha

 

Alright so this morning I pulled the hubs and locked them up manually. It fixed all the problems I was having, both the obvious lack of 4wd and the clicking from the tcase when shifting on the fly. Guess it's time to order up some Rugged Ridge hubs

 

Sounds good. I also haven't noticed any changed in Mpgs since I got my manual hubs. I was getting 11 mpg before and am getting that now. Lol.

 

Wow that seems low or maybe I'm just naive haha but I know I got 19-20mpg on a 230 mile trip doing about 75mph all the way down

 

I'm all city driving. So it's terrible. I usually get 200 miles on my 19.5 gallon tank. Give or take.

 

On my daily commute I'm probably somewhere around 13mpg. Now you've got me curious haha I guess I'll just calculate it