What always worked for me on the older Yukons was to get on some gravel road as hard surface just made it worse, then roll backwards in reverse slowly while still moving shift into neutral and then take it out of 4Lo. Might have to do it more than once but it always worked.
Stuck in 4 wheel low
- Thread starter 6977Gregyver
- Start date
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Agreed.
The front wheels need to be able to “slip” a bit on wet roads or loose gravel when turning.
rockola1971
Full Access Member
At a complete stop put tranny in neutral. Then put Tcase into neutral. Then shift Tcase to 2wd,4wd HI or Auto 2wd. And dont ever think about racing the SUV in 4wd LO unless you want to pick the pieces of your Tcase off the road. 4wd LO makes a YUGE amount of torque at the wheels(At low vehicle speed), it is not designed for any form of normal use driving.
I have a 2003 yukon with this problem occurring intermittently. The first and most simple way to get it out was turning it off, then back on, then go into neutral and HOLD the 2wd button for 10 seconds, even if it seems like nothing is changing, hold it down. If nothing after 10 sec changed the only other thing that worked for me was popp8ng the dash cover/ face off off, removing the 4wd switch. Unplug the harnesses from the switch and plugging them back in.
I've had this problem for a while and almost always holding the 2wd button has worked, even when it seemed like it wasn't doing anything. After 10 seconds it would "klunk" out if 4 Lo. I learned that from a random comment on a forum somewhere.
Hopefully this helps. I just had this issue a few days ago and tried multiple things. Pulled fuses, disconnected battery, but the only thing that worked was removing the switch, pushing the wires into the connectors (just in case) and putting it back together. Once I turned the car back on I was able to go back into 2wd.
Usually I dont lose the lights on the switch, but I did the last time it got stuck. If I have lights, normally holding the 2wd button worked.
I should have made it more clear. Mine randomly will go into 4wd on its own. I don't keep it on auto. It hasn't done it will driving. Sometimes after I start it up, it will randomly be in 4lo or 4 hi and I always have to turn it off, then on, then hold the 2wd button for way longer than you would think you would need to. The last issue I had was different. No lights in the switch.
You might want to scan for the 4wd "C" codes. Better yet, use a Tech 2 or other capable scanner to compare the "commanded" vs "actual" mode. I had success diagnosing mine, where the actual mode wasn't what was being commanded.
This could easily be a symptom of the encoder motor going bad on the transfer case. Those can be replaced as a unit, or just the internal range position sensor.
Best to get a capable scanner on it to diagnose.
Yea I need to get the proper scanner. Will HP tuners scan for those 4wd codes? I've got HP tuners and credits still.
Some history on this yukon. When I bought it he had posted the 4wd didn't work. I did all sorts of research and bought it. He had removed the front driveshaft. Imagine assuming because it was getting stuck in 4wd.
My research pointed to the shift motor/encoder.
I tried the replacing the switch first because it's a simple thing and it did nothing so I just returned it. Then I bought the new shift motor as a whole. So the shift motor and encoder in there are only a year and a half old. Granted, parts these days aren't exactly great. On top of that, encoders are a sensitive thing.
After replacing that it was perfect for about a year. Then about 6 months ago it randomly would be in 4wd when I would start it up. All I would do is turn it off, turn it on, hold 2wd button, and it would go back into 2wd. But the symptoms are inconsistent. Sometimes it would be in 4wd hig and sometimes in 4lo. Usually 4 hi. You don't get much noise going in and out of 4Hi. But 4lo is different. You get that solid clunk.
I'm hopeful that the encoder is fine and that the switch is needing to be replaced (since it's the original one as far as I know). But either way. Since that last issue I had, then played with the switch, it hasn't done it again yet, and ice had to use the 4wd a couple times since then. It went right in the got it right back out when I needed it to.
If it does it again. I'll try to get the 4wd codes read somehow. I thought when I researched this a while back that HP tuners couldn't read the in depth stuff from the 4wd system but I could be wrong.
Thanks for the tips.
rockola1971
Full Access Member
Are you 100% sure that when you are doing a cold startup and the indicator light is showing the Tcase in a gear you did not select before you the shut the vehicle off? Unless you have a button(s) intermittently shorting or their respective wires, it is just about impossible for the system to select a Tcase gear by itself. Are you sure that the lights are not just showing the Tcase in a gear that it is truly not in. This is a common problem with a dirty/worn encoder position sensor (commutator). Ive drove my 03 Tahoe LT down the road before and it showed it in 4wd lo which it obviously wasnt at 40mph without screaming its guts out onto the road. Running the Tcase from 2wd to 4wd HI or Auto 4wd and then back to 2wd would clear it all up.
I have seen the front axle stuck engaged even though it wasnt being commanded by the 4wd system to be engaged. This is usually a mechanical problem with the front actuator on the front axle or within the diff.
Do the lights flash when you press the buttons? When you're slowly rolling in neutral and press either 2 or 4hi that button should flash for a little bit. If it doesn't there might be something wrong with the button panel. If it does flash but goes back to 4lo being solid something else is wrong that stopped it from shifting.
I experienced this exactly, too, except that I had to cycle the ignition to clear it. And it came back occasionally until I fixed the encoder motor.
Just to rule it out, you could check and clean the two ground points that are on the body mount on the frame under the driver's door hinge. One has two wires and the other has one. Don't just eyeball them, remove and clean them.
