got a question. 05 f150 here. when i switch it to hi or lo 4x4, the light comes on. the truck feels like its in 4wd but the front end isn't locking in. front right axel turns while in 4x4 but tire does not. neither does the driver side. I'm thinking the axel splines are stripped out in the hubs. watcha think? Just looking for suggestions before i tear into it. thanks!

 

Do you have manually locking hubs?

 

nope, just the switch on the dash. if i punch the skinny pedel, the 4x4 engages at a high rpm. Not good for the truck though. Basically, swith to 4x4 hi or lo and the front end don't lock in. Splines on the axels maybe stripped? 85k miles and i'm the recent 2nd owner.

 

You have to be in neutral to switch into 4Lo, but maybe try coming to a complete stop, put it in Neutral, and try 4Hi. I'm stumped and not sure what else to suggest for you to try. Might have a bad engagement of the transfercase?

 

When you engage 4x4 put your truck on reverse and let it roll for a few feets, and see if 4x4 is working.

 

yea i'm doing all of that when i switch to 4x4. (neutral, rollback, park) its thinking its in 4wd, even in 4lo you can really feel the truck pull in that lo gear. my only prob is the front tires aren't locking in. I saw somewhere where theres vaccuume in the front for the 4wd.

 

took the truck for another drive today. i can lock it in 4x4, but when i punch the gas its poping out of 4x4with a terrible grinding noise. jacked up the front and in 4x4, i was able to turn the front tires by hand, clicking sound coming from the front right. possible the front right isn't engaging fully? vaccume leak?

 

It has to be a leak in the vacuum system then. When your truck is changing to a engine speed and vacuum changes its not able to hold enough vacuum in the lines to stay completely engaged. Get a vacuum tester and find your leak. Also, tes your two check valves and the vacuum resevoir. Check valves are on your vacuum lines close to your iwe solenoid and resevoir is behind battery. You are definitely leaking somewhere.

 

Awesome. This is what i was wanting to hear. I'll trace the vacuume lines tomorow, and if no visible leak i'll go to the parts store and get a tester. truck has 85k miles and liiks like it was a pavement pounder the 1st 80k miles. probly never locked in 4wd. I'll give an update tomorow if i find anything out.

 

Maybe your IWE solenoid, they tend to go bad, cause water can leak then and get into the system.