I reckon I must have been driving over a year with engaged IWEs. You just don't know. I checked recently when I had the truck on the lift. You really should check for this everytime you get the chance.

With the wheels is the air run the engine (in 2WD). Turn the front wheels by hand and look to see whether the front driveshafts are turning. If they are your IWEs (vacuum operated front hub engagers) are not functioning.

Twas just the little valve which gets wet. $35 later I'm on the road with less wear to my front end components and better fuel economy.

Ed

 

Thanks for the info! Will check mine when I get a chance!

 

I tied some extra long zip ties onto my front drive axles. You can hear them slap the chassis when they turn. It helps if your experiencing a small leak that you lose vacuume when driving but not at cruising speeds.

 

I put a chalk line on my front drive shaft once to check, drove around a while checked it and it hadn't moved, that is something you can do to check also.

 

All good ideas. Folks just need to know. There must be thousands of trucks driving around with engaged IWEs and the owners just don't know.
Ed

 

If its a small vacuum leak it'll engage/disengage half way and tear up stuff. I found this out myself. The iwe wheel end hubs are 82 bucks on tousleyfordparts.com, anywhere else they are 110+ Dealer wants 124 a piece for them. I just ordered one for my driver side as I replaced the pass side a few months ago back in the winter months. The seals blow out and they don't hold vacuum like they are suppose to. I've got vacuum hose taped off and closed up so it'll stay engaged on the one side and won't mess something up till the new part gets in. You can hear the axle turning going down the road they do make a small sound as it turns...

 

I've always thought about disconnecting the vaccuum system so the front end stays locked in. The small amount of extra fuel and wear this would cause would be worth it not having to worry about all the issues with this system.

 

checked mine and the are working just fine..... I guess the crap mileage is due to the 305/65/18s and 2" level. lol