Stuck in 4WD??

ts684

Original poster
Member
May 29, 2013
81
Third owner of 09 Envoy SLE. 120K mi. About 4 wks ago, when in Vt, I need the 4WD. It seemed to go in and out slower than I remember my 04 Envoy did. Back home , cycling in and out in warmer weather, seemed to work OK. Then about 2 wks ago, just before I was going to drive to Vt again, it gets stuck in 4WD. I turned control to A4WD, quite a few blinks, then steady. Turn to 4Hi, quite a few blinks, then steady. Turn back to A4WD, quite a few blinks, then steady back on 4Hi!! Turn to 2Hi, quite a few blinks, then back to 4Hi!! All this happened while driving straight, about 30mph. When I reached a corner and had to turn, steering was stiff. Drove short distance home and tried going forward and back with control turned to 2Hi. Plenty of blinks but still in 4Hi. Dang, have to drive to work the next day. Start next morning, 2Hi light is lit!! Drive to Vt. and back in 2Hi, no snow, car has a locker and I added to bags of sand. Take to dealer after getting back home, they can't find anything wrong!!! Didn't charge me either!!! Now I'm afraid to put in A4WD or 4Hi, don't want to get stuck. When I drove back and forth trying to get out of 4WD in my parking lot, I could hear the TC motor cycling continuously when I turned to 2Hi.
 

budwich

Member
Jun 16, 2013
2,027
kanata
likely that the shift motor has some "electrical problems" reading where the position is. Try only activating different modes when sitting at idle (or neutral as required by the 4w lo) and see if the result / response is different.
 

ts684

Original poster
Member
May 29, 2013
81
Changed fluid 3 days ago just in case. Drained fluid was a nice blue. Oddly, I never changed fluid in my 04 Envoy, and it had 241K mi. , no problems with it. If I run through positions while stopped, would it be less likely to lock-up? Rereading my post, I noticed I forgot something. Earlier in the day, I took the car to the carwash and sprayed a lot of water underneath to remove road salt.
 

budwich

Member
Jun 16, 2013
2,027
kanata
depending on what is being selected, a number of "systems" come into play. Some of those may have some "less than good operation" at "speed" while others don't care as much. I have noticed on mine that selecting 4w auto is not a "dependable" under power as it is at idle. Same with de-selecting (back to 2w). This is in cold weather. In warmer climes, it operates well.
 

ts684

Original poster
Member
May 29, 2013
81
If it sticks in 4Hi or A4WD again, will turning car off, setting selector to 2WD and restarting likely to return me to 2Hi? How about removing both 4WD related fuses? I don't have the opportunity to mess with it right now and this is my daily driver. I know that driving in 4WD on dry roads is really bad.
 

gmcman

Member
Dec 12, 2011
4,656
You could try removing the encoder motor from the transfer case and see if it returns to 2WD operation.

Also, if the encoder is stuck on the front then again by removing it could possibly release the actuator.

The encoder motor on mine went bad around the 200K mark on the transfer case... but obviously that's a case by case basis.

When you turn it from 4HI to 2HI, do you hear any of the encoder motors operate? If so, from when to when? 4HI to A4WD or from A4WD to 2HI? Or both...or neither?
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
depending on what is being selected, a number of "systems" come into play. Some of those may have some "less than good operation" at "speed" while others don't care as much. I have noticed on mine that selecting 4w auto is not a "dependable" under power as it is at idle. Same with de-selecting (back to 2w). This is in cold weather. In warmer climes, it operates well.

Maybe because of the crap congealed grease they use in the disconnect, the actuator is having a harder time to engage or disengage, especially if the engine hasn't warmed up yet and the oil pan hasn't warmed up the disco.

When putting it in A4WD, only the disco engages (one whir in front) and in 4HI, the encoder motor engages (one whir under). When going from 2HI to 4HI, you should hear both one after the other (IIRC, disco first, then encoder).

4WD not working? Step inside.

 
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ts684

Original poster
Member
May 29, 2013
81
When trying to go from 4Hi to 2Hi in my parking lot, I could hear the TC motor under drivers seat continuousley cycling like it was stuck or something. Did not hear the front disconnect, but wasn't listening for it either. Too bad there's no way to lube the disco without taking it apart.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Could be the encoder motor. Take it out and cycle through the modes and watch the movement.

Using pliers, try turning the shaft on the transfer case. If having trouble there, could be the transfer case.
 

ts684

Original poster
Member
May 29, 2013
81
Could be the encoder motor. Take it out and cycle through the modes and watch the movement.

Using pliers, try turning the shaft on the transfer case. If having trouble there, could be the transfer case.
What should be the position of the TC shaft when in 2HI?? When I replaced the TC motor a week-10 days ago, I had to rotate the shaft in the TC so I could install the motor. Motor came with a plastic "key" to hold it in position. I assumed that the TC shaft would have to be in a corresponding position. Is it possible to turn the shaft on the TC too far?? Also, replaced the axle disconnect. Was not hearing anything from the front.
 

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