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4 Wheel Drive/SUVs/4 wheel low will not disengage

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Expert: - 1/18/2007


Question
I have a 1998 expedition.  I can't get the 4 wheel low to disengage

Answer
Pat,

To give you a simple answer would be extremely hard without looking at the truck.  This problem is usually a transfer case problem, and could be as simple as a linkage problem.  Some of vehicles use a vacuum, or electrical switch/solenoid on the transfer case, which has vacuum, or electrical lines running to the front differential that can be pulled loose, or the switch itself can be faulty.  If your transfer case is shifted electrically, then it may be just a bad ground to the transfer case.  These problems can be traced out fairly easily.

I would suggest that you purchase a repair manual, and try to trace out the front wheel drive section, starting with the front hubs.  A Chilton's or a Hayne's manual can be purchased at most auto parts stores for $20, and they have a lot of information on basic trouble shooting, and repairs. These manuals are designed for a year or range of years for specific vehicles, and are invaluable if you are planning on doing any repairs yourself.

Another thing to try, would be to have the transmission, transfer case, and differentials serviced.  This is simply changing out all of the fluids.
There is a slight chance that there are some dry components that are causing some drag on the shifting mechanism.

Carl

4 Wheel Drive/SUVs

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Carl Brandt

Expertise

Will discuss suspensions, lifts, lockers along with tire suggestions. Trail ratings and possible requirements needed for specific type of trails. Safety equipment and what you should carry with you. Certified off-road instructor. I am not a mechanic, and 4-Wheeling is a hobby, so if I can't answer a technical question it is due to my mechanical knowledge being related to vehicles that I have owned, or have worked on. I do not have manuals on all vehicles.

Experience

40 plus years of 4 wheeling in a variety of vehicles. At the present time, my major off-road rig is a 94 Jeep Wrangler with a spring over and a 1 1/2" suspension lift. This gives me a total lift of 7" or so. I have lockers front and rear. I have removed the track bars, and sway bar for maximum articulation. I am running a stock 2.5 ltr 4 cylinder with a Jacobs ignition along with a cold air high flow filter. It has 4.56:1 gears with a Dodge NV4500 transmission along with a 3.8:1 Atlas II transfer case. This gives me a final ratio of 105:1 in low gear/low range. Other vehicles I own, are a 96 Ford F-250 with a 6" lift, posi rear end, 36" Hummer tires, 5 speed with a fuel injected 460 ci engine, an 87 Samurai with an 8" lift, Ford 9" rear end with a spool, Chevy Dana 44 front end with an electric locker, 5.88 gears, 16% reduction in high range and a 6.5:1 low range with 35" Baja Claws, and a stock 2003 Grand Cherokee Overland. Trails I have run are the Rubicon (10 times), Dusey Ershim, Fordyce Creek trail, McGrew trail, several trails in Moab, Utah along with local monthly runs.

Organizations
Lost Coast 4x4's Cal 4-Wheel Corva UFWDA Blue Ribbon Coalition

Education/Credentials
Certified off-road instructor - Certificates in engineering/electronics

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