You are here:

4 Wheel Drive/SUVs/2003 GMC 2500 HD 4wd

Advertisement

Expert: - 2/2/2010


Question
4wd will not engage. replace actuator today

Answer
Wes,

I am not that familiar with this model.  From what I understand, there are a couple of issues with this vehicle.  If it has the full time transfer case, it is very important to maintain the fluids as it has clutch plates in it (very similar to a posi-traction rear end) and they can start slipping without the proper maintenance.
The other problem is the front differential has to lock in.  It has an electrical motor that locks up the axles for the front wheel drive.  If there is low or no voltage going to this unit, the front end will not work.
I would suggest that you purchase a repair manual at your local auto parts store.  They cost around $20 and are a great source when trouble shooting or repair of your vehicle.

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.