4x4 won't engage

[Fr0z3N]

99 sport 4x4 5spd

I followed this

97-01 4-door and 96-00 Sports
Your control knob should say 4auto, 4high, 4low.
First, we need to narrow it down to a transfer case issue, or a front axle issue.

Step 1) Jack up the front end and place it securely on jack stands.

Step 2) Verify that the front driveshaft turns by hand. When turning the front driveshaft by hand, the front wheels should turn. (If only one turns, don't be alarmed. One wheel sometimes has more resistance in the brakes, bearings, or CV joints. This is normal)

Step 3) Start the vehicle and let it idle in PARK. Engage 4high. DO NOT PUT THE VEHICLE IN GEAR!!! Crawl underneath and see if you can turn the front driveshaft.
**If you can turn the front driveshaft, the transfer case is not locking. This could be due to a mechanical issue with the transfer case itself, or an electrical gremlin with the control system. Start a new thread with the results of your checks, and we'll go from there.
**If the front driveshaft does not turn, the transfer case is locking properly and we need to continue searching.

Step 4) With the front wheels in the air, engine idling in PARK, spin one front wheel. The other wheel should spin the opposite direction. If both wheels spin in opposite directions, then the front axle *should* be properly engaged. Take it for a test drive (after safely lowering it to the ground, of course). If the front wheels do not spin in opposite directions, there is a problem with the front axle. Start a new thread with the results of your checks, and we'll go from there.

Got to step 3, with the front in the air, car idling and 4x4 High on, I can still spin the front wheels.

It's been like this since january. It use to click or hop when turning but that eventually dissapeared

 

[gijoecam]

Your transfer case is not locking. Check for power at the brown wire when idling in park. Use a digital multimeter to check it as a test light may not show any voltage. (has to do with the type of signal sent to the case)

-Joe

 

[Fr0z3N]

use a multimeter on what setting?

 

[gijoecam]

DC voltage, something less than 15V, but greater than 4V. Stopped and at idle, with the duty cycle at a minimum, it may only read 4-6 volts. That's why you need a multimeter and not a test light... a 12V test light won't necessarily light.

 

[Fr0z3N]

Ok I reread what I'm supposed to do, while the truck is running, in neutral I'm supposed to spin the front wheels (cv shafts) or the front AXLE? I spun the wheels (cv shafts) I forgot there was an axle. Did I do it wrong? I'm gunna double check if you tell me I did it wrong

 

[Fr0z3N]

Ok so regardless if the truck is off/on, 4auto or 4high I can't spin the front axle. I believed a long time ago when I got the hop on turns that my truck was stuck in 4x4 but I just left it and the hop slowly started getting less aggressive and now doesn't hop.

 

[gijoecam]

You're talking about the front driveshaft, right?

 

[Fr0z3N]

yeah the 1 that goes to the front diff from the t case.

 

[Fr0z3N]

bump?