(Solved) TV stuck in Low 4WD... Help!

[Arefbee]

We have a weekend trip planned and now the Yukon acts up! I may be driveway camping just to keep the kids happy.
Here's the story. The check engine was flashing and the codes read as knock sensor. Took it to the shop since I needed to have it fixed faster than I would have time to do it.

Got it back two weeks ago and all has been fine until today. Dropped it into 4WD low because I had to drive on some soft grass and didn't want to spin the tires. Get back on gravel, hit the button for 2WD High - the selector LED flashes, then stays on 4 low.

Took it back and forth on the driveway, reseated the fuse (LEDs unlit when pulled) and no luck.
I don't think I can even take it to the shop in this condition unless we happen to get a foot of snow, which is not forecast. Already posted on the Tahoe/Yukon forum but looking for any help I can get any where I can get it.

Anyone ever have any issues with a GM TV getting stuck in 4LOW? I am hoping the shop left a vacuum hose ot wire connector unhooked somewhere. If anyone has a good diagram of the system, I'd be overjoyed.

[wyo700]

These do no work off of vacuum if I remember correctly but electric actuators. One in transfer case and one in the front diff. Did you try going into 4 HI first and was you truck in neutral while trying all this.

[Ford Idaho]

I know a guy who had to drive 45 miles in low 4 because the actuator died.

He was not a happy hunter.

Try unhooking the battery for about 90 seconds then try again..

[wyo700]

I did work some that the front actuator snapped off in the diff. But they were in 2wd and wouldn't go into 4wd. So the actuator could have tried to go back and snapped. But now that I think about it that actuator in the front diff would have nothing to do with it being in 4 low. It has to be something with the transfer case.

[Arefbee]

Originally Posted by wyo700

These do no work off of vacuum if I remember correctly but electric actuators. One in transfer case and one in the front diff. Did you try going into 4 HI first and was you truck in neutral while trying all this.

All electric is what I have found elsewhere, so maybe a pinched or corroded wire... It seem like it is trying at least.
Initially tried in park, then moving, and tried all modes. I can see this may be a ball-peen to the transfer case moment.

[Arefbee]

Originally Posted by Ford Idaho

Try unhooking the battery for about 90 seconds then try again..

Heading outside right now... finger crossed.

[tugger]

My truck [Chev] will not go from 4 low to 2 wd, I have to hit 4 hi and wait a second for it to lock in and then hit 2 wd. not sure if yours is the same or not? I assume you have already tried that.....

[Blackrock]

Find an open street or area, drive in reverse, let of the gas and shift to neutral all in one motion and let it coast for a ways. If that don't work do the same thing going forward.

Your drive train is bound up in a torque loading and the electric motor isn't strong enough to pop it out of 4L.

[JFM-jr]

My Dodge and the Chevy Blazer I drive at work will not shift out of 4 lo unless the transmission is in Neutral.

[Acableguy06]

Are you sure its IN 4wd or just going off what the light says? Does it shift like normal or is it shifting quick and wont get to full speed? The reason I ask, my wifes Yukon would do some funny things with the actuator lights. Usually would do it while in 2wd and would read as being in 4wd low when it really was not. And when you push 2H it would just flash and the light would stay in 4wd low and it was not. I had to replace a sensor inside the actuator on the side of the transfer case.

[Arefbee]

Neutral!!! OK, it worked. Now as long as we don't have any snow, I stay out of bogs or PA sink holes (one swallowed a whole build in Allentown once) and most importantly stay out of 4LO until after our next trip, I will be OK.

Thanks to everyone for the help. You guys are awesome!

Still haven't gotten a single response on the Tahoe/Yukon forum.

[Ford Idaho]

Originally Posted by Arefbee

Thanks to everyone for the help. You guys are awesome!

Still haven't gotten a single response on the Tahoe/Yukon forum.

Not a problem.

That's sad and funny at the same time...

Have fun on the trip.

[glen1971]

Glad you got it figured! Just remember when switching between 4HIGH and 4LOW to make sure that your transmission is in Neutral first...

[wyo700]

Originally Posted by glen1971

Glad you got it figured! Just remember when switching between 4HIGH and 4LOW to make sure that your transmission is in Neutral first...

Now you know. But you had to have done that to get into 4lo also. O well I bet you won't do it again.

[Arefbee]

Always made the change in park before. Neutral from now on.

Thanks all again!!!

[Lynkage]

Originally Posted by glen1971

Glad you got it figured! Just remember when switching between 4HIGH and 4LOW to make sure that your transmission is in Neutral first...

Glad you got it!!
My Fords need to be in neutral as well to get them out of 4 low.

[mrayb02]

My Fords need to be in neutral as well to get them out of 4 low

Our Navi won't shift either way unless it's in neutral. Park won't allow a shift either to low or from low. My .02

Ray

[glen1971]

Originally Posted by wyo700

Now you know. But you had to have done that to get into 4lo also. O well I bet you won't do it again.

Do it again?? I was commenting to the OP's issue.. I've known about this "trick" since I was 12...

[Arefbee]

Originally Posted by glen1971

Do it again?? I was commenting to the OP's issue.. I've known about this "trick" since I was 12...

I thin he was agreeing with you...

I must admit I have not had a GM on-demand sytem before. I've had an 89' Subaru, 88' Mitsubishi (on the fly, but no low setting, just push the button on the shifter), Toyota (locking hubs...) and my current Chrysler full time AWD. Always something new to learn on each rig. I did neglect to RT*M (read the *@#$%ing manual) in this case tho, but I was convinced the last guy to work on the truck had hosed something up.

That all said, I have learned that lesson at least... now to find another!

[Brother Les]

Why did you not look in the owner manual?

My F-250 will go in 'on the fly', but to take out..... neutral.