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4 Wheel Drive/SUVs/2001 GMC Jimmy 4x4 not working

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Expert: - 5/21/2007


Question
I have a 2001 Jimmy where the 4x4 will not engage. I have replaced the vacuum actuator, cable, and cable housing swirch, as well as the dash selector switch. None of the indicator lights illuminate on the switch even after replacement, and there is definitelt no action from the transfer case or differential when any of the switches are depressed. Where to next?

Answer
Erik,

Change the fluid in the transfer case, and check for metal shavings, or any other indications of faulty components.

Install a new, or additional ground cable to the transfer case, as many times, a bad ground can cause a similar problem.

Make sure that you are getting voltage/power to the switch, as you may have a broken wire, or something as simple as a bad in-line fuse that you aren't aware of.  Then, check the vacuum lines going to the vacuum actuator for the proper amount of vacuum to make sure that they are functioning properly.

After doing this, you may have to go to a reputable transmission shop (preferably one that specializes in 4-wheel drives) and have them check it out.

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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