vacuum/binding problem!
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Junior User
Joined: Jun 2006
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vacuum/binding problem!
on my 01 f350 4x4,i have a problem with 4x4 engaging/disengaging...i have read some of the other posts,and i think it is the vacuum solenoid,which iam waiting to get in from the ford dealer(i have done some process of elimination,and that is what it looks like it is)...as of right now, my front axle shaft seems to be spinning freely,but i have a bit of torque bind when driving down the road...it isn't like it is in full 4x4,it's like it's only partially in 4x4 because the binding isn't as strong as it is when it is in full 4x4....will this binding go away when i install the new vacuum solenoid?...the way i understand it it takes vacuum to engage,as well as disengage...any insight would be appreciated....B.M.
Postmaster
Joined: Mar 2007
Posts: 2,612
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From: Dunwoody, GA
I think my solenoid has gone bad as well. I've unplugged it and haven't had any issues, but my symptoms were the same. Every now and then when I was slowing down I could hear some gears grinding and when I came to under 5mph it would go "CLUNK". The 4x4 light would flicker on and off as well.
Have you tried unplugging it to see if that's the issue? Make sure you have a free spinning drive shaft before you unplug it.
Have you tried unplugging it to see if that's the issue? Make sure you have a free spinning drive shaft before you unplug it.
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Junior User
Joined: Jun 2006
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vacuum-binding problem!
mine is really strange..i unplugged the vacuum pump because it won't shut off...i took one out of my buddies 05(they are the same to 07 iam told),and when i hook his solenoid up,the pump shuts off.As i have been waiting for the solenoid to come in,i have unplugged the vacuum pump so it doesn't run non-stop and cause premature wear....but what i have noticed is,as my last post explained, that iam getting that binding feel....i thought the driveshaft was spinning freely,but when i just went out to check,as it was parked in the driveway,it isn't spinning freely....at least not sitting in the driveway....so,does it lock and then unlock,cycling back and forth or what...i don't know,and i don't get it!....i especially don't understand how it can seemingly lock and (when i say lock,i mean the driveshaft not spinning freely),and then unlock(driveshaft spinning freely),when the vacuum pump isn't even plugged in....what would cause the driveshaft to "lock" and then "unlock" like that?...iam stumped!
Tuned
Joined: Oct 2006
Posts: 361
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From: Eagle River, Alaska
My 04 had the pump replaced by the prev. owner shortly after purchase. So looking through threads here and such for the cause, I found it to be a some what common deal for EFSO systems. As for the unlocking and locking, I would suggest checking the state of the hubs by trying to rotate the u-joints next to the spindles instead of the drive shaft. This will tell you which side may be still locked. Turning the drive shaft doesn't give enough isolation to pinpoint a hub. IMO, with the vac servo disconnected the hubs would not re engage with out manually turning the hub point selector ***** to do so. You may have one that didn't disengage with servo( vac pump combo) before disconnecting it. There is a service bulletin pertaining to hub> stub axle interference issues, (tech. service bulletin)TSB 04-18-5(99-04 superduty). Seems it was cause for some intermittent engagement issue or such though. Good hunting.
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Joined: Jul 2002
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From: Long Island USA
Sounds more like the needle bearings where the axle stubs ride are dry.
With the wheels straight ahead, with the hubs unlocked, reach around the back of the wheel and turn the u-joint by hand. It should be somewhat hard to get moving, but once moving be nice and smooth and not gritty or ratchety.
With the wheels straight ahead, with the hubs unlocked, reach around the back of the wheel and turn the u-joint by hand. It should be somewhat hard to get moving, but once moving be nice and smooth and not gritty or ratchety.
