1999, F250 Super Duty 7.3L powerstroke
 

Welcome to FTE, racer280465.

It's the hub. Changing the ESOF hubs to a manual hub is a very common modification. Warm Premium are highly recommended.

Thank you Redford, what a mine of information this site has been, both before buying the beasty, and now!

Thank you, you have made me smile a lot more than i was earlier lol. So is the process to change the hub not to ounerous? I have done the job on landrovers in the past, but never anything American, I am new here, and at the moment have limited tools, mine are not yet arrived from the UK, and won't for sometime yet :-)

The lockout hub is very easy to change. Remove hub cap. Use a pliar tto remove the large snap ring. Pull hub off. Reverse procedure to reinstall. You don't even have to take the wheel off but it may need some tapping with a rubber hammer to loosen.

The automatic function on these trucks use vacuum to engage. Most likely the inner wheel seal is shot. You really don't want to tackle that unless you are a purest and want everything working like new. My advice is to disconnect the vacuum line to the front axle and manually engage the hubs when necessary. No other changes are required. the dash switch will still engage the front axle at the transfer case, but not the hubs. Don't leave the manual hubs engaged as this causes the front axle and drive shaft to spin constantly making for poor performance and lousy gas mileage.

If you do leave these vacuum hubs operational, sooner or later your vacuum pump will burn out. You will know this by the defroster operating at all times as it is about the only other thing uses vacuum. And with no vacuum it defaults to defroster mode.

One other point that may interest you. If you are like many others and seldom require 4 wheel drive, find another hub to go with your bad one, disassemble and remove the inner gear of the the lockout hubs. Install on both sides. This will completely eliminate any drag from the front axle. I get an extra 3 MPG by doing this. I carry the functional hubs and a pair of pliars along and when necessary they can be change out in less then 5 minutes. Believe it or not, even with new hubs disengaged they still produce enough drag to keep the front axles and shafts spinning along. Remove those gears, and that don't happen.

Hope this all helps you out.

Thank you! That sounds like a LOT better than I was expecting! Good tip re gutting the hubs. Will the end of the drive shaft still be adequately supported with no guys to the hubs?

Where might i find the vacuum pipe to the front axle, I can't see see one at the hub end and i don;t have the dash switch for "on the fly" changing, so i suspect there is no vac pipe for the front axle?

Ooops! I guess I need to stop assuming things. I thought you had the switch so I guess you can forget about the vacuum. But if you have manual system, your hubs should say Lock and Free, not Lock and Automatic. I think that's what threw me off. In the manual system nothing is automatic. Are you sure you even have the correct hubs?

As for the hubs, now that you mentioned yours were not electric you would need to check it out a bit closer. I've been doing all of this since 00 when I bought the truck with no ill effects yet. The axle shafts are still supported with the drive gears removed. But I have the electric 4X4 shift with an auto trans.

I wonder about the folks calliing it a shift on the fly as my manual clearly refers to it as automatic. It states you can shift up to 55 mph but never with the rear wheels slipping. It also says it takes up to 45 seconds to complete the shift for safety reasons. ????

Sorry for the misunderstanding.

Hi again, they are definately marked autolock/lock, but I only have the lever, I checked lol.

I did have a fiddle with them when we left on Friday, the drivers side one went in with a satisfying clunk, the passenger side however felt like it wasn't right, and not "clunking" into place.

They could very well be the wrong hubs, I have NO idea at the moment, but I did turn them both to lock, and the passenger side shaft was definately turning with no movement on the wheel, making some very unpleasant noises.

I will pull iy tomorrow, but you still think the shaft will be ok? If not, is that a HUGE issue?

No worries about misunderstanding, I probably explained it badly, thank you for your help :-)

thank you Redford, what a mine of information this site has beenhttp://www.wengmj.com/a125.jpghttp://www.wengmj.com/uk.jpg

can you PM me or give me some more information on that. I have a 2000 F250 v10 4x4 super duty and i have a rotating squeak (the squeak sounds like an old rotating playground thing) It never really speeds up but it definitely starts when i am rolling. Its a constant speed and I believe its just the front axle spinning like you said when you were talking about the automatic on the fly 4x4s. Id like to pick your brain a little bit about this so I can find this squeak and deleting the vacuum automatic switch line saving gas is interesting.

PS i may have just rambled but contact me and Ill explain it more clearly.

UPDATE

So pulled the hub off today. It appears everyone was correct! The inner "carrier" was sporting a number of cracks, and there was much aluminium debris inside the carrier, suggesting that the internals of the hub are a little past their best!

Couple of questions, the wheel hub was totally devoid of grease, should it be packed with grease, or should it be greaseless?

What sort of replacement would everyone recommend? I have found this one on Ebay Warn 38826 Premium 4WD Manual Locking Hubs 1999-2004 Ford Super Duty F-250 | eBay just want to know people's opinion, I can get a pair for over $100 less, are these worth the extra cash?

Many thanks in advance.