4X4 Issue - Diesel Forum

blasko · 05-12-2009, 01:40 PM

I have an 02 Ex and am having the following problem withmy 4wd

When I engage 4wd, I get an indicator light that its in 4wd as it should, and on dry pavement the front end grabs. But once i get on the sand, I have no front end traction at all. I need to lock in the hubs in order to run in 4wd. I believe it may be a vacuum issue as the defroster kicks on when i turn the switch from 2wd to 4wd.

The hubs are new and function, and the dash displays 4x4 which i guess means the relay works so how do I go about vacuum testing the system?

Thanks.

Btw, I have limited tools, knowledge

, and patience

purplehorn1977 · 05-12-2009, 01:43 PM

get a smoke machine is the easiset way other wise you can be there for a long long time and never find it. the leak that is. or just say to hell witht the auto and get out and lock it in that what i do on our trucks that way i know they are engaged.

Bruce1954 · 05-13-2009, 10:02 AM

Quote:

Originally Posted by blasko

I have an 02 Ex and am having the following problem withmy 4wd

When I engage 4wd, I get an indicator light that its in 4wd as it should, and on dry pavement the front end grabs. But once i get on the sand, I have no front end traction at all. I need to lock in the hubs in order to run in 4wd. I believe it may be a vacuum issue as the defroster kicks on when i turn the switch from 2wd to 4wd.

The hubs are new and function, and the dash displays 4x4 which i guess means the relay works so how do I go about vacuum testing the system?

Thanks.

Btw, I have limited tools, knowledge

, and patience

Not sure about the limited knowledge part; stating that the defrosters come on with the 4WD is a BIG clue.

Yes you have a major vacuum leak

There is a scheduled service required at 60 or 70K on the front hubs and includes new vacuum seals [I have had a set hanging above my work bench since 70K now at 110K

] I think the part number is F81Z-4A322-AA also at one time there were instruction on this site or a related one on how to do the service and what grease to use and NOT to use and so on.

If someone can tell us where this link is I need to print it out as well!

You could pull the hose(s) off the axle then plug them then turn on the 4WD if the AC is on and not the defrosters the leak is in the axle.

If it still goes to defrost then you have a leak between the valve on the right inner fender and the axle.

It should not be that hard to find it not like it is under the dash or hidden in the body some place.

I would bet that it might be the hubs.

Bruce

MotionMan · 05-13-2009, 07:12 PM

The 4x pump runs for 45 sec, then stops, if there is a leak you will loose the 4x then, I ditched the air system but yours is a little different since the defroster comes on, yours is most likely outside of the axle.

DieselSteve2008 · 05-14-2009, 09:22 AM

Mine did the exact same thing and it was the vacuum solenoid mounted on the passenger side fire wall under the hood, ford dealer said it is very common for these to go out, it cost me about 70.00 and it was very easy to install, I think it was two bolts and 3 vacuum lines total.

keith_1963 · 05-14-2009, 10:44 AM

Mine is doing the same, except I don't have any problems with heater controls. I will have to check the selanoid. I also have the problem that I cannot turn my hubs manually, even putting vice grips on them, so I bought the rebuild kit to lube them, I hope that's the issue.

blasko · 05-19-2009, 09:49 AM

Thanks for all the replies. I will test the system with the info given. I really appreciate all the help.

Zapped277 · 05-19-2009, 09:08 PM

i can't bleve it -- this happend to me this weekend on my 02 -- i am leaning on ditching the auto hubs for a set tof manul warns i dont trust anything vac to work inportan stuff

but i could be jated with the problems with my gm heating /cooling stuff

TXANGLER · 05-19-2009, 10:25 PM

i went with the milemarker's in stainless steel.