4WD LOW Doesn't Engage

[DennisG01]

I have the (4) push-button set-up. 4WD Hi engages and works, but Low does not. The light on the button just keeps flashing. It tried to get it into Low via both "park" and "neutral". Any ideas? I let it flash for a good 10 seconds and I tried a few times on different days.

[JTodd]

One thing that I have found is that if the truck is rolling slightly - only slightly - in neutral it has an easier time of it (hit the button as the truck ideals forward, maybe with some brake applied, shift to neutral). Is it doing the same thing going to 4wheel high first, then to low?

[MJEasly]

My 4WD failed 2 times. The first time, the case froze in 4-lo. I had it towed to the dealership and they replaced the actuator motor for about 500. The next failure was about a year and a half later and was due to a failed wiring harness. During the troubleshooting process of the first failure, the tech made pinholes all over the harness to test signals, which caused the harness to rust out later.

Do you hear the actuator motor working at all (i.e., is it just stuck in 2-hi or can you go from 2-hi to 4-hi)? If you don't hear the actuator motor working, then eliminate the possibility of bad/broken connections before replacing the actuator motor. Inspect the harness and reseat the connections.

If the problem is only in 4-lo, then I am inclined to think that 1) there is a physical problem within the case preventing 4-lo engagement or 2) a sensor is providing inaccurate information that will not allow the engagement of 4-lo. There is a manual way to engage 4-lo, but i don't have that procedure here with me right now. If you can engage 4-lo using this procedure, then see if it shifts normally - it may be just stuck. Otherwise, you may have a sensor issue.

I hope this helps.

[DennisG01]

It shifts fine from 2WD to 4WDHi. I tried shifting to 4WDLo both from 2WD and from 4WD with no luck. I forgot about the rolling forward thing. I'll try that tonight.
Can you normally hear the actuator motor over the engine? Or, will the truck shift into 4WD if the engine is off?

[MJEasly]

I put my truck up on jackstands (very dangerous - do so only if you know what you are doing) to test the engagement of the tcase. You can definately hear the actuator motor running. You may even hear the front diff lock IIRC.

[diesel65]

This system will only allow you to shift into 4lo when in neutral.
When you shift into 4hi, are you sure the front differential is engaged. A bad front actuator may prevent you from engaging 4lo, causing the shift button light to flash.

[DennisG01]

The 4WD Hi light comes on solid and stays on. When I put it into 4WD Hi, I didn't get any wheel spin going up a steep dirt hill (both with and without the boat attached). Also, no wheel spin coming out of a steep boat ramp.

Could there be a separate fuse (or something) for 4WD Lo?

What/Where is that wiring harness? Is it something specific to the Low range, or is the harness common to both Low and High?

[noelb]

Dennis, if you check the owners manual it may have a process to get it into low4 if it won't do it any other way. In my manual it is page 4-7. It says:

NOTE: if the transfer case does not shift into 4Lo, the switch may require adjustment. With the transmission in neutral, press and release the 4lo switch. While the indicator is flashing, shift the transmission into P(park). Wait until the light stops flashing before shifting the transmission into gear. This will get you into 4Lo. Take the vehicle in for service.

Cheers

Noel

[DennisG01]

I'll try that when I get home tonight. Thanks!

[DennisG01]

I tried the manual way of putting it in 4WD Lo. It didn't work. I don't know if that means it was the wrong procedure, or if it means Lo just plain doesn't work. By the way, I checked through my manual and could not find this procedure.