You are here:

4 Wheel Drive/SUVs/Blazer jumps into 4-wheel-drive

Advertisement

Expert: - 10/6/2007


Question
Hi Carl,
I have a 1999 Chevrolet Blzaer ls, 6-cyc, four-wheel drive automatic, 107,000 miles, well maintained. Lately, the Blazer has been jumping into 4-wheel drive on its own. The lights on the dashboard switch flash and if I'm driving at road speed it goes into 4-hi and if I'm going slow or stop while the lights are flashing, it goes into 4 low. Swiches out easily when the 2-hi button is pushed. No pattern to it. Recently had front wheel bearings replaced. This happened a few years back when the bearings went bad the first time. (They've gone bad twice now, but that's another story) I know the wheel bearings should have nothing to do with it but I have to wonder. Thanks for any ideas you or anyone else might have on this probelm.

Answer
Rodney,

Sounds like your 4-wheel drive switch, or wiring is shorting out.  Check out the switches, and wiring.  If you have a fuse to this circuit, pull it and see if you still have the problem.  Other than that, make sure you have a good ground going to the transfer case.  Actually, going into 4-wheel drive on pavement or hard surfaces is extremely hard on the drive train, so this needs to be repaired asap.

Carl

4 Wheel Drive/SUVs

All Answers

Answers by Expert:

Ask Experts

Volunteer

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

©2012 About.com, a part of The New York Times Company. All rights reserved.