4 wheel low drops out

[jrjr2u]

I plow 4 driveways with my 97 sport. Sometimes, not all the time, the 4 wheel indicator lights go out and it is no longer in 4 wheel drive. I always plow in low range. When this happens, I shut the truck off, start it back up and the 4 wheel low light comes back on and things work normally again. This only happens maybe once a plowing session, sometimes twice. For the most part it functions fine.

I have tried moving the switch to auto and 4H then to 4L but this never works. I have to shut the truck off for it to return to 4WD. There are no noises, it just shuts off for some reason.

Edit-
The 4WH and 4WL lights do flash briefly before going out and losing the 4WD.....

Thoughts on what to look at first?

 

[jrjr2u]

I have read all the stickies but none seem to apply to this situation. Maybe so, but how is the shutting the truck off part applicable? This is my 2nd year of plowing with the truck. It started this right at the beginning of plowing last year. I had never had the truck in 4L before that and have owned the vehicle for 4 years or so only using it occasionally. It doesn't seem to be getting worse and I thought maybe it might rectify itself. The condition is staying about the same though.

 

[Glen4X4]

Haven't experienced your problem...But do have a suggestion, how about swapping in a manual transfer case and this will void the problems of the 4405 you have now since you are stressing the transfer case.

 

[jrjr2u]

I take it real easy. I mean real easy. There is not much stress on it, no more than, I would say, if one were off roading. Good idea though.

Does anyone think that the problem may be like in this photo of the motor? Could this be intermittent and fixed by shutting the truck off?

 

[jrjr2u]

By the way, that photo is from the sticky up top...... not of mine. I am just trying to get some ideas before I tear into it.

 

[KPT]

I'd start with cleaning the range shift motor contacts. There's a thread here somewhere on it.

I'll throw a theory out there that the contacts have an intermittent connection, The GEM sometimes can't see that the t-case is locked in low or high and is cutting power to the TCC.

Do a brown wire mod, it would help with troubleshooting.

 

[jrjr2u]

It has been a while since I read about the brown wire mod so I just read it again. How would this help with troubleshooting in my situation? I know that 4 wheel is disengaging from the lack of traction.

Also, are these the range shift motor contacts that you refer to?

and

 

[jrjr2u]

anyone?

 

[username1]

does your 4 on the fly work?i have a simliar problem, my truck will kill the 4wd once i hit 30mph, no 4 on the fly, the lights will flash till i put in 2wd the i can shut the truck off turn it back an it works fine.i think its a speed sensor issue i am changing this weekend.might be the same thing on your truck ill let you know if it works

 

[jrjr2u]

Yea mine works fine. I never exceed 45 with the plow on and a lot of times I have it in 4x since the roads are bad. No issues in 4 high so far, only 4 low and that is only occasionally.

 

[gmanpaint]

I would do the simple things first.

Check and change the t-case fluids. Fresh fluids will only help, and you can see whats going on by looking at the old.

Remove the 2 hall sensors on the case and clean them. Be gentle and take care when removing them.

If the old fluids are anything but a nice pinkish color, it has been compromised. Broken down by time, heat, or water. Look for ANY foreign particles such as, copper, or plastic.
Copper fragments are from the clutch pack. Plastic fragments can be from the shift fork. Steel fragments can be from a variety of items.

Move on to the front diff. Check & change the fluids in it. Binding in this, could cause the front shaft to make the t-case react and shut off the clutch in the t-case. This is not an easy job, as the you either have to drop the diff to remove the cover, or pump out the old via the fill hole.

Does your ABS light come on? From what I have been led to believe, the 4405 gets its signal from the ABS system to adjust the clutch accordingly. ABS light on=ABS off. This means no signal to the 4405, and loss of 4x4. Check the hubs and the ABS sensors (3) lines & connections.

Just a few things to check out to help you troubleshoot.

 

[jrjr2u]

No ABS light now. It was on a few years ago but shut off with a front hub assembly change. No issues since.

I do have a suction gun and will change out the fluids. Going to look up the hall sensors now... pics and stuff. Thanks