Think I narrowed it down to a problem with the hub lock solenoid. This is on my 02 F150 4.6 4x4 SC

Symptoms: Front diff engaged in 2H, but not locked from xfer case in 4x. Feels like I am towing or riding the brake. No noise other than more "tire hum" sound which I think is just from the axles turning. So, slower take off obviously... Also found that while in 4x, hi or lo, getting loud squeals from the diff. Maybe the solenoid isn't allowing a proper lock up? Not really binding up, but definitely not smooth. I was on dirt to test.

No visible or audible vacuum issues from tubing- but I haven't climbed all through the truck either- quick look.

Am I missing something? One thing to note, just replaced a leaking water pump...was leaking down into and around the skid plate. Is there a component in there off the diff that may have taken on some water and shorted or been otherwise compromised?

Ordered a solenoid to replace tomorrow, and will replace some weathered vac fittings while at it...

???

 

Note that you don't have locking hubs - it's an internal diff lock. Front axles are always turning.

 

Then that may mean I am on the wrong track...I was thinking my hubs were the issue...

When I make a turn at speed, I get front tire chirping- it ain't that easy to chirp 35's...and there's that feeling of either pulling something or like the brake is engaged. When I let off throttle, I don't instantly slow down, and there is that hum underneath as if it were low tire pressure, which is not the case.

I am stumped. Hubs??

 

No, you don't HAVE hubs. Read this thread:

https://www.f150online.com/forums/19...-engaging.html

There is an actuator that locks and unlocks the front axles internally within the differential. You also need to make sure the transfer case itself is engaging and disengaging.

 

Thanks for that, I appreciate it...but doesn't seem to be my issue.

I'm gonna pull the wheels off and see what I can see. Problem is, All my past 4x4's were older model Fords and Chevys...this is an 02 and I've been out of the 4x world for about 10-12 years so I gotta not only re-learn some things, but also learn my truck.

All I know is I gotta figure this thing out...

 

Pulling the wheels off probably isn't going to help, being that you have solid hubs.

 

Yeah, I mean to look at the brake situation...anything that looks awry. I am surely not the best mechanic around, but if I can get to it, I can turn the wrenches. I'll be looking over the vac lines while at it.

 

UPDATE:

You just never know what you'll find until stuff starts coming off. Had a bad axle- bearings broken and shaft flopping freely inside. Explains all the noise while in 4x...

While putting on new axle, put on new brake pads and bled the system- new brake fluid.

Still have that feeling of pushing something. Took some video and enlisted help in watching the actuator do its thing switching from 2H to 4H/L. It's working, but is there enough travel movement to disengage? Thinking maybe not,

So...the problem is not as bad, but definitely noticeable- probably just different with the new axle. No noise picked up, but definitely that feeling that the front end roll is under resistance. It does not feel like I am pulling something, there is something causing rolling resistance. I keep wanting to circle back to the front diff...I had new gears put in about 6 weeks ago, but this came on suddenly. Got under again and had help in the cab with the switching. I hit the actuator and linkage with some CLP as it was all I had...

More chasing, but I am beginning to think it is a broken shift fork... If nothing else, I am getting a quick education.

 

UPDATE:

Surprise! The shift fork and mechanism is great. Strange for a 12 year old truck. But...

The problem persists.

The journey continues...

 

Can anyone tell me- The front shift lever on my front diff: which way is engaged in 4x? To the passenger side, or toward the diff/driver's side?

Right now I have the actuator out of its mount and tied off so I can tie off the lever either way for testing/short term 2H workaround until I get back from a quick deer hunt.

Help!

 

This blows. Bought a Posi-Lok. Diagnosis woulda been about a hundo, so is my deductible if a covered fix. You know with after-market warranties they are little more than a discount program if you have one.

Got the lever tied off in 2H for now. No 4x4'n for a week or so. Got a deer hunt this weekend and an elk trip in 3 weeks. It'll be fine.

Hope this all was some sort of help for somebody having similar issues!

 

In case anyone is led to this with similar symptoms- here is an update:

After being stumped for so long, I decided to change out both hubs and bypass the vac diff lock system with the manual Posi-Lok cable system.

Back to normal. Whew! So far, all internal differential components are solid. My vac system may have been ok, but why wait for an eventual fail? Now I control fully when I engage that front diff.

Next up, I will be replacing upper control arms/bushings, inner/outer tie rods, Pitman arm, etc. A rebuilt front end that should nearly outlast my use of the truck. Already installed lower control arms, hubs, and Bilstein 5100's all around.

Happy maintaining y'all!