2005, 2500, 6.0, 98000mi, auto. Truck will not shift into four low. Tried different speeds in natural. Light flashes on control panel but no shift, four high works. I am thinking some type of solenoid problem, but sure where to begin. Scanner does not throw a code. Or is this something that should go into the shop. Thanks

 

Problems like that are frequently caused by non use, and letting the Fluid become "goopy" because of that.
Try a Fluid change first, and be patient, use a 5mph rolling in natural attempt to let it shift into 4lo. May take several try's before it shifts.

 

this means what?


It will only go into 4lo with the vehicle stopped and transmission in neutral.
do not make this shift moving even if the manual says under 5mph


its attempting to make the shift but cannot complete it; possibly from a condition not being met....moving is one. review your owners manual.


does the transfer case make the shift into neutral...the dingy towing position?


it may not be showing a fault if:
-its working properly and your not shifting under the right conditions
-your scan tool can't read codes from the transfer case control module

 

What I meant, the manual tells you to shift to four low while in neutral going 3-5mph so tried speeds from 0-5mph So Tech what you are saying only shift to 4 low when stopped and in neutral.
This makes more sense than what the manual states. If I could go 5mph in natural why would I need any 4 wheel drive. Yes it does go in the into neutral position. One thing it does go into 4low maybe 1 out of 20 tries.
Thanks

 

Again, I think you need a Fluid change, and repeated attempts to engage 4lo.
I believe it just needs to be exercised to start working right.

Once you get it to change, don't stop there. Change back and forth several times, given you've started wiping the goop out of the way. Also, when and if you do get it going, you should change into 4lo about once (or more) a month, to keep things changing well.

 

Well I tried the neutral thing no change. I do get all the lights at start up and I do get the light to blink when I try to engage 4 low. SW when you say fluid change are you talking about the tranny or the transfer case or both.

 

Well, if you haven't done the tranny, it too, but,
I was referring to the XFer Case.

It's possible that it hasn't been changed in so long, it just won't do the slides necessary to work. You did say it changed rarely, that makes me think Fluid !

 

Thanks SW. Got cold so when to tranny shop to have it changed. This shop is considered the best in the area. Told him what was going on he also that it might be sticky fluid. Put the scanner on it and thats when he got stumped. He could not figure out why no code showed up for non shift. He then thought it might the 3 way switch. Well it is going in next Friday will post the results. Thanks

 

That sounds reasonable to me. You don't get a code when there's no problem. I still think it's just stuck. Now that you got fresh Fluid in it, you need to keep trying to make it change till it does.

 

switches are a common problem. a weak encoder motor is another possibility that would cause this.