I'm starting this thread as a change of topic from another thread.

Myself and Born2BowHunt have the same issue with our truck.

Here is a copy of BowHunt's post

I keep getting "service 4wd" I only seen the light once. Then I turned the truck off and restarted it and haven't seen it again until recently. Now everytime I go down a dirt road (everyday) thats 'rough'; the "service 4wd" light comes on and all the illimination goes off on the selector switch. I have ruled out the selector switch, so I am thinking maybe a loose ground??? But don't know exactly where to look. Or any other ideas you guys have. I would really appreciate it.

Thanks for all your help so far,

 

I'm getting the same message on my DIC "SERVICE 4X4

When the message comes up, my indicator flashes but won't go into 4X4

Other time it goes into 4x4 with no problem, later when I try to take it out of 4x4 it just flashes and won't come out of 4x4.
I put it in Park
I try it in Neutral
I park it, turn truck off and restart until it finally works.

After my son and I give it a good thorough checking over. It turned out to be the transfer case electric actuator

While it was in 4x4 and it won't come out 4x4 I could still hear an actuator working. Turned out that was the front axle actuator working to engage and disangage the front axle. It was still in 4x4.

I could crawl under and lightly tap the actuator and it would work.

 

Were you in four high, or four low? My truck won't shift out of low unless the truck is rolling ever so slowly and the transmission is in neutral.

 

My issues are shifting from 2wd to 4wd High

 

hmmm....Check your fluid level?

 

My truck has 134,000 km on it. At 100,000 ALL the fluids were replaced.

 

Hmmm....Interesting. Whats that convert to miles as lol.

 

100,000km = 62,000 miles

 

Ok. Do you come to a complete stop when you try shifting?

 

No From 2wd to 4wd I always do it on the fly. But even from 2wd or even 4wd high to 4wd low I will still shift during a slow role to aid in synchro