I found out 2 snows ago this was not working. When I bought the truck about a year ago, I never noticed this not working before but really didn't try it. fficeffice" /><O></O>

This is my first diesel (2000 F350 Crew Cab, 7.3), so I’m learning as I go. I’ve updated a few things over the past year and it seems to be running better and better. <O></O>

I researched this issue and from what I’ve found so far, the root of the problem seems to point toward the vacuum pump or leaking hose. <O</OI still think there could be another component involved, but did not find enough info to clarify.<O></O>

I bought it from a Dealer “as is”, and think the prior owner was either “girly” or just dopey. Ie., tires on front are a size larger than those in back. Also, batteries were way undersized (could have been dealer), fuel filter was dark black, fuel gage was not working (stuck on full) etc.,

Notes;<O></O>
- Blower not working. Defrost and heat to feet does work. <O></O>
- 4x4 light comes on but not which switched to the 4-low<O></O>
- The hubs turn and I think they are engaged<O></O>

Questions;<O></O>
- If new hoses are needed, where would I find them? (part #? link?)<O></O>
- What else could be the culprit? <O></O>
- How do I know the hubs have turned far enough to be engaged? <O></O>

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A few things I’ve done so far include;<O></O>
Fuel bowl rebuild, correct battery sizes, Hutch Mod, rebuild right side of engine wire harness, new brake line (front to rear). <O></O>
<O></O>

 

First check the rubber vacuum lines from the frame to the knuckles, if cracked etc just go to any auto parts store and get a few feet of new vacuum line. While your in there remove the nipple that screws into the hub for the vacuum line and make sure it's clean. I've seen them clog with dirt an even the rubber hose and stop the hubs from working. On my dad's 2000 7.3 the vacuum pump on the front passenger fender went bad 50 bucks for a new one for ten dealer and it's been good for three years now

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I'd add four correct sized tires to my upgrade list ASAP as well

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Do you have manual hubs or automatic hubs? Your title says manual, but your post starts to talk about vacuum. If they are automatic and not locking when in the AUTO position, you should be able to turn them to the LOCK position and have 4 wheel drive. If you have manual hubs, and 4WD is not working, your issue is not vacuum related. If you have automatic hubs they will say AUTO and LOCK on them.

 

Thanks for the responses. I think I may actually have something going on with my GEM. A bunch of weird electrical issues started coming up this week too.

Still going to check the hoses. With all the rain the past few days I didn't get a chance to do much of anything.

 

I believe they are automatic. I just have the **** to switch to 4x4 on my dash, but still have to manually lock the hubs.

I still don't have 4x4 when I manually turn them though.