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#1634 of 1936 Information on 4X4 problem, 2004 Expedition
Oct 17, 2006 (1:17 pm)
After several trips to the local Ford dealer due to my front hubs making all sorts of grinding noises in 2w high, it was discovered that acid from the battery was eating holes in the vacuum lines mounted on the firewall right next to the battery. The noises were worse in 2wd high as the vacuum dropped going up grades. The 4X4 system apparently relies on engine vacuum through these lines to keep the front hubs disengaged while in 2w high. Due to loss of vacuum, the hubs were trying to engage or something and thus all the clanging, grinding. On one occasion the entire 4wd was inoperative. Also appears that the new heat shield around the battery sags into and soaks the vacuum lines with acid. Not sure? Poor design to use such flimsy vacuum line material and in close proximity to the battery.
Solution. Do a vacuum loss test, replace, patch the vacuum lines as needed and keep the battery clean as possible. Replace the battery if necessary. Also added a plastic tie at home on my own to keep the vacuum lines from direct contact with battery or battery shield. Also periodic careful washing of vacuum lines with garden hose has helped.
As additional information, the shop foreman indicated the system has a built-in guard to keep the 4X4 from self destructing when the above vacuum is lost and all the grinding noises start.
#1635 of 1936 Re: Information on 4X4 problem, 2004 Expedition [nbx]
Oct 18, 2006 (5:55 pm)
Ya know something. . . ive had problems with a little looseness and play in the steering rack and the groaning/grinding from the front wheels has been getting worse and just about all the time. Ive brought my Expy into the dealer and they couldnt even comment on the groaning/grinding, said it was normal. . .NOT. . . funny to have this post come along cause today when i started to hear the groan/grinding, i put it in 4AWD. . . NO NOISE. . .NOTHING. . was perfect and silent. . .also I have always said that the steering rack feels noticeably tighter when in any of the 4wds. I would assume that the "variable speed assist steering" is run on vaccuum also and may be tied in with all this somehow. So NOW i can take it to the dealer and ask them to check the vaccuum lines associated with this. AMAZING how you came across this finding. . .THANK YOU THANK YOU THANK YOU.
#1636 of 1936 Re: Information on 4X4 problem, 2004 Expedition [razzmaniac]
Oct 18, 2006 (7:22 pm)
Does your front end clank when you put it in 4AWD while the vehicle is moving? If so, there is a TSB for that which might also address the groaning/grinding. I had it done to my 03.
#1637 of 1936 Re: Information on 4X4 problem, 2004 Expedition [zman3]
Oct 19, 2006 (7:49 am)
It doesnt clank when i put it into 4awd. . . but does SOMETIMES if i put it into 4hi or 4lo. . . aweful sound like grinding gears. . . All this though usually only happens when the truck is warmed up, especially the groaning/grinding sound, so that totally tells me its vaccuum related. ALSO with all of this vacuum issue. . . my tranny clunk hard into 2nd gear on the down shift at 20mph on decelerration EVERYTIME. . . Once again i wonder if this is all related to a vacuum problem seeing everything started to happen all at the same time, the loose steering at higher speeds, the tranny clunk and the groaning/grinding in the front end. Definately gonna bring it in with these posts to give the mechanic a heads up on what im talking about.
Thanks again for all these posts. . . makes life so much easier when explaining things to dealers. I dont feel like im going crazy anymore. . .love my truck and glad to hear its not a lemon. . . lol
#1638 of 1936 Re: Information on 4X4 problem, 2004 Expedition [razzmaniac]
Oct 19, 2006 (8:58 am)
Hope my post helped.
Mine too would stop the grinding noise by switching to AWD. Obviously by being in AWD the system was no longer trying to keep the hubs locked out. We had to resort to AWD on the way back from the beach at Hilton Head Island this summer. On the hills in NC/SC the vacuum would drop with any extra gas pedal at all in 2WD high and all the grinding would start. Stopped immediately in AWD.
With reference to the time my 4wd system quit working, there was a switch (low cost as Ford prices go) that was bad. Not clear whether the battery acid had a role--but
the switch is mounted on the firewall right in the area where the battery acid damaged the vacuum lines.
Speaking of frustrations, it was only after the second or third repair that the dealer found the acid was causing the problem. Earlier had said the vacuum lines may have been rubbing on a sheet metal edge.
P.s. Thought about removing the battery shield (bag looking thing)as it sags over against the above vacuum lines near the firewall. But, don't know the function of this new high tech bag apparatus? Ha!
#1639 of 1936 Re: Information on 4X4 problem, 2004 Expedition [zman3]
Oct 19, 2006 (9:20 am)
I had a 2003 Expedition 4WD that had to have the "S" spring fix which is apparently the same repair you mention.
Except for the time when the 4wd went out 100% and had to have the switch on the firewall replaced, my 2004 has not had any noises or malfunction at all in 4WD in either high or low.
Up to 60,000 miles on my 2004 NBX. Overall low trouble and feeling I might drive it for a while now that gas is down around $2. Would like to have the extra bit of power of the 5.4 3v from 2005 and up. The only other significant probelm for my 2004 has been that 3 of the 4 NBX's off-road steel wheels are bad out-of-round from the factory per the local tire stores. Wheels made by Hollander? Anyone know? Need to find some decent wheels--driving me nuts, wheel balancing no help.
#1640 of 1936 Re: Information on 4X4 problem, 2004 Expedition [nbx]
Oct 19, 2006 (5:20 pm)
IS it ok to keep it in 4AWD all the time even on the highway??? I want to keep it in 4AWD until i can bring it to the dealer.
#1641 of 1936 Re: Information on 4X4 problem, 2004 Expedition 
Oct 19, 2006 (8:13 pm)
Yes, OK all the time in the 4AWD setting wet or dry. But, only wet or snow in 4wd high or 4wd low. The 4AWD results in a 1/2 mpg or so fuel mileage penalty, but no problem at all using 4AWD for days on end on dry pavement.
P.s. I felt confident before my post under number 1634 above that my experience with the vacuum leaks and the hub noise in 2wd would be of value to others. This mystery front 4X4 hub noise was solved as a joint venture between the Ford dealer shop manager, the Ford District Rep and me. The first time we could not duplicate the noise on any hills nearby, but the Ford District Rep happened to be there that day and knew about the problem from visits to other Ford shops. He outlined steps to solve the problem based on my description. the District man however did not mention battery acid as the culprit with the vacuum lines. Amazingly no harm to the front hub assembly has been noted even though it sounded like the left front wheel was being ground off.
#1642 of 1936 Re: Information on 4X4 problem, 2004 Expedition [nbx]
Oct 20, 2006 (7:05 pm)
How did you get in touch with the Ford Distric Rep?????
I would SO love to contact mine in South Florida about my loose steering rack. The dealer just brushes it off that "it drives better then most" and "it would be difficult to find the problem". Contacting Ford themselves does no good, they just tell me that i need to see a dealer, and even though theres a TSB for a nibble in the rack, theres no TSB for loosened racks. Pretty lame, huh. Anyway, if you can let me know where i can find out who my distric rep is, that would be a HUGE help.
Oct 21, 2006 (9:56 am)
We just got an 03 Expy eddie bauer. Our problem is that it only came with one key and no alarm. In fact we don't even have the door key pad code.
WE LOVE IT!!
Does anyone know how to get the key pad code?? Does the dealership charge for this information?