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My 4x4 is not engaging and I really, really need it :)

Hello everyone!

I have a 1500 1996 4x4 full size pickup truck, manual 5 speed transmission floor stick. (No a push button to get into 4x4)

I destroyed my original transfer case and rear driveshaft and over the summer I replaced both. I did have a small issue with the furthest electrical on the transfer case’s plug not closing tight like the one towards the front did. So, when I tried the truck in 4x4 and did not see the front tires lighted in my 4x4 floor stick displayed on the console, I thought it was caused by that rear electrical plug. When I set the truck in 4x4 low, I could feel the good old feeling of the traction, so I thought I was done.

Since we got into ice conditions, I realized quickly that my front tires are NOT turning when I set the truck to 4x4… I guess that is why the light is not lighted in the 4x4 display board console.

Any help would be greatly appreciated since my truck is basically a sitting duck without 4x4 during the Winter months…

Many thanks,


Is it a Dodge?? They use a Micky-Mouse vacuum operated servo on the front differential in place of locking hubs…

UPPPPSS , Sorry, it is a Chevy Truck

Are the axles tuning? Did you damage the locking hubs along with the transfer case?

It’s a UPS truck?

UPS truck??? It is a Chevy 1500 pickup full bed. I damaged the transfer case because I put to much weight on the truck, broke the rear driveshaft, so I cleverly drove the truck on 4x4 mode so using the front tires until the transfer case exploded! I cannot see how I would have damaged the locking hubs…

“(No a push button to get into 4x4)”

Does this mean you have the push buttons on the dash (Instatrac or Autotrac) or a lever on the floor?

If you have Instatrac or Autotrac, check the vacuum lines under the hood that connect to the vacuum actuator that engages the front axles. Whiel I was trying to fix the Autotrac on my 2000 Blazer, I discover most of the vacuum lines were disintegrating. No vacuum leaks yet, but I will be replacing them in the spring.

The transfer case was working properly, but the front axle was not being engaged. The 4x4 light would keep blinking when pressed, eventually it would switch back to 2wd. There is a vacuum valve switch that controls the vacuum to the actuator. After I replaced the switch the 4x4 started working.

The switch is on the firewall for the Autotrac system, I believe the Instatrac system has the switch mounted on the transfer case. This link explains it better than I can.

Ed B

What do you think also transfers the torque to the wheels?

Thanks for your reply Ed,

I change to 4x4 by a leer on the floor…

BustedKnuckles, I know that the hubs needs to be lock in order to the front tires to turn, but they were working even after my transfer case exploded (a piece of the side wall broke and pieces actually came out) … even with that damage, I drove the truck inside my garage for the transfer case replacement and rear drive shaft. With that in mind, Why would the front tires stop getting torque?

“I change to 4x4 by a lever on the floor”

If you shift the transfer case with a floor mounted lever, the electrical connections must serve only to energize the dash display lights…

MILLIONS of drivers manage to operate their Chevy trucks WITHOUT blowing up the drivelines, overloaded, whatever…When my Dodge W-200 spit out the rear drive shaft (U-joint failure) I drove it for a month in the “front wheel drive” mode without any problems…You seem to have more than your share of trouble with driveline parts…Transfer cases don’t “explode” unless the driver does something to MAKE THEM explode…How about overload the truck, go to 4-low, first gear, rev it up and dump the clutch. That’s always fun (and expensive)…

Well, not fun for me… I am a contractor and I treat my truck like the most valuable tool I have since it gets me, my tools and material to my job. The day I damaged the driveshaft was because I had a huge load of blue stone. Then, since it was summer and I was working 14 hours a day, so I drove on my front tires for two months until as I said, it exploded as I was going up a hill. I turned around drove home and had to rent a truck until I got the new transfer case and driveshaft replaced.

I bought that truck 5 years ago and has being the most reliable transportation I ever had.

Many if not MOST Chevy’s use transfer cases made by Chyrco/Dodge.