4 wheel drive issues, appears to work in 4low but not 4 high

There are a few potential issues that could be causing your 2004 GMC Envoy SLT to go into 4-low but not 4-high or 2-wheel drive. Some possible causes include:

1. Transfer case issues: The transfer case is responsible for controlling the engagement of the different drive modes. If the transfer case is damaged or malfunctioning, it may not be able to engage 4-high or 2-wheel drive.
2. Shift motor issues: The shift motor is responsible for controlling the engagement of the transfer case. If the shift motor is damaged or malfunctioning, it may not be able to engage 4-high or 2-wheel drive.
3. Vacuum issues: The vacuum system is responsible for controlling the engagement of the transfer case. If there is a problem with the vacuum system, it may not be able to engage 4-high or 2-wheel drive.
4. Wiring issues: The wiring that controls the transfer case and shift motor can become damaged or corroded over time. This can cause the transfer case to not engage 4-high or 2-wheel drive.
5. Control module issues: The control module that controls the transfer case and shift motor can fail. This can cause the transfer case to not engage 4-high or 2-wheel drive.

It's best to diagnose the issue by a professional mechanic, who can perform a proper diagnosis and repair the issue. They will be able to determine the specific cause of the problem and recommend the appropriate repairs.

Assuming yours is the 2 gear stick layout this is roughly how it works.
ONLY CHANGE BETWEEN 2 AND 4 WHEEL DRIVE WHEN STOPPED, IN NEUTRAL AND WITH THE PARKING BRAKE ON!!
The smaller gear shift should be to the left of the normal gearstick.
It should be in the fully forward position. This means it is in 2 wheel drive, high ratio, for normal road driving. (Rear wheels).
Pulling the stick back ONE notch engages 4 wheel drive, high ratio. Used for snowy, icy, slippery conditions as well as light off roading. (Keep the speed under 50mph).
Pushing down and back another notch engages neutral in the transfer box. This means ALL drive is DISCONNECTED even if you use the normal gearbox.
**Try to avoid this one**!!
Pulling the stick back the last notch engages 4 wheel drive, LOW ratio. This is for the more extreme off roading conditions such as VERY steep hills. Not usually used in normal day to day driving.
The two fully forward positions, (2High and 4High), will be the ones used the most.

Have you had codes checked ? While connected to a good scanner that will check transfer case switch to show if switch is working, and it could be the switch on the side of the transmission.

2 speed electric shift transfer case problems #1 jack up truck place on 4 jack stands. Start and select 4 high position in drive release brake ad watch front driveshaft does it turn "yes" problem is axle actuator on passenger side of differential not engaging axle shaft. "no" apply brakes bring to a stop engage low range does low range work "yes" internal transfer case problems "no" electric transfer case shifting motor failure.

On these issue, there are few solved help links for troubleshooting the issue easily.-------

Click the link below: ---

No 4x4 light on dash?

http://repairhelpcenter.blogspot.com/2011/12/no-4x4-light-on-dash.html

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4X4 Truck makes roaring noise in the front end?

http://schematicsdiagram.blogspot.com/2012/01/4x4-truck-makes-roaring-noise-in-front.html

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Car will not go into 4WD high or 4WD low?

http://schematicsdiagram.blogspot.com/2011/12/car-will-not-go-into-4wd-high-or-4wd.html

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No 4x4 light on dash?

http://repairhelpcenter.blogspot.com/2011/12/no-4x4-light-on-dash.html

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4 wheel drive system will not disengage?

http://technoanswers.blogspot.com/2012/01/4-wheel-drive-system-will-not-disengage.html

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4WD light is flashing and beeping? NO 4WD high?

http://schematicsdiagram.blogspot.in/2012/02/4wd-light-is-flashing-and-beeping-no.html

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2002 Jeep Wrangler: 4WD Idiot Light is ON?

http://technoanswers.blogspot.in/2012/06/2002-jeep-wrangler-4wd-idiot-light-is.html

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Traction control switch will not engage on 4WD High or Low

http://whoisbyme.blogspot.com/2012/10/traction-control-switch-will-not-engage.html

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4WD light flashing and 4WD will engage after few minutes

http://repairhelpcenter.blogspot.com/2012/10/4wd-light-flashing-and-4wd-will-engage.html

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2008 Toyota Tundra: 4x4 Wheel Drive Light is Flashing?

http://technoanswers.blogspot.in/2012/05/2008-toyota-tundra-4x4-wheel-drive.html

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4x4 front differential will not engage the axle on ford?

http://technoanswers.blogspot.in/2012/02/4x4-front-differential-will-not-engage.html

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4x4 will not engage on Ford F150?

http://technoanswers.blogspot.in/2012/02/4x4-will-not-engage-on-ford-f150.html

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Dodge Ram 4x4 light keeps flashing

4X4 LOW LIGHT IS FLASHING ON DASH

http://technoanswers.blogspot.in/2012/09/dodge-ram-4x4-light-keeps-flashing.html

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Ford 4x4 front wheels will not engage?

http://technoanswers.blogspot.in/2012/02/ford-4x4-front-wheels-will-not-engage.html

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These details will help.

Thanks.

On any suv with 2 and 4 wheel drive options 4 low generally means that the transmission is in 4 wheel drive low gearing option so that the most possible torque is transferred to the wheels by way of what would be called a granny gear. What you will need to do is check your 4 wheel drive settings to see if the transmission has been put into this option which is either on a separate shift lever or a push button either on the shift handle or on the dash. Your owners manual should also direct you to where the selector is at.

First, start checking the fuses an there is also an electrial activaced switch at the transmission or transfer case that may be bad.

95-96
Your control knob should say 2wd, 4auto, 4low.

First, we need to narrow it down to a transfer case issue, or a front axle issue.
Step 1) Jack up the front end and place it securely on jack stands.
Step 2) Verify that the front driveshaft turns by hand. When turning the front driveshaft by hand, the front wheels may or may not turn. Do not be alarmed if they don't turn. This is normal for your vehicle.
Step 3) Start the vehicle and let it idle. Place your foot firmly on the brakes, place the transmission in NEUTRAL, engage 4low, then place the vehicle back in park. DO NOT ENGAGE ANY GEAR!! The lurch as the transmission engages could cause the vehicle to lurch and potentially fall off the jack stands.**If you can turn the front driveshaft, the transfer case is not locking. This could be due to a mechanical issue with the transfer case itself, or an electrical gremlin with the control system. Start a new thread with the results of your checks, and we'll go from there.
**If the front driveshaft does not turn, the transfer case is locking properly and we need to continue searching.
Step 4) With the front wheels in the air, engine idling in PARK, spin one front wheel. The other wheel should spin the opposite direction. If both wheels spin in opposite directions, then the front axle *should* be properly engaged. Take it for a test drive (after safely lowering it to the ground, of course). If the front wheels do not spin in opposite directions, there is a problem with the front axle. This could be due to a mechanical problem with the diff, or a failure of the center axle disconnect to engage the passenger side axle shaft. Start a new thread with the results of your checks, and we'll go from there.

Troubleshooting the CAD on a 95-96 is a bit more involved than I want to get into here, and the problems can vary widely. This'll get you started.


97-01 4-door and 96-00 Sports
Your control knob should say 4auto, 4high, 4low.
First, we need to narrow it down to a transfer case issue, or a front axle issue.

Step 1) Jack up the front end and place it securely on jack stands.

Step 2) Verify that the front driveshaft turns by hand. When turning the front driveshaft by hand, the front wheels should turn. (If only one turns, don't be alarmed. One wheel sometimes has more resistance in the brakes, bearings, or CV joints. This is normal)
Step 3) Start the vehicle and let it idle in PARK. Engage 4high. DO NOT PUT THE VEHICLE IN GEAR!!! Crawl underneath and see if you can turn the front driveshaft.
**If you can turn the front driveshaft, the transfer case is not locking. This could be due to a mechanical issue with the transfer case itself, or an electrical gremlin with the control system. Start a new thread with the results of your checks, and we'll go from there.
**If the front driveshaft does not turn, the transfer case is locking properly and we need to continue searching.
Step 4) With the front wheels in the air, engine idling in PARK, spin one front wheel. The other wheel should spin the opposite direction. If both wheels spin in opposite directions, then the front axle *should* be properly engaged. Take it for a test drive (after safely lowering it to the ground, of course). If the front wheels do not spin in opposite directions, there is a problem with the front axle. Start a new thread with the results of your checks, and we'll go from there.


'01-'03 Sport and '01-'05 Sport Trac
Your control knob should say 2wd, 4high, 4low

The transfer case in these trucks functions essentially like the 1st-gens' 13-54 t-case. (i.e. it uses a lockup collar engaged by the transfer case shift motor) The troubleshooting procedure is very similar, but you don't need to worry about hubs or center-axle disconnects engaging.

Step 1) Jack up the front end and place it securely on jack stands.
Step 2) Verify that the front driveshaft turns by hand. When turning the front driveshaft by hand, the front wheels should turn. (If only one turns, don't be alarmed. One wheel sometimes has more resistance in the brakes, bearings, or CV joints. This is normal)
Step 3) Start the vehicle and let it idle in PARK. Engage 4high. DO NOT PUT THE VEHICLE IN GEAR!!! Crawl underneath and see if you can turn the front driveshaft.
**If you can turn the front driveshaft, the transfer case is not locking. The shift motor could be falsely reading an incorrect t-case position, or it could be a mechanical issue with the case itself. Start a new thread with the results of your checks, and we'll go from there.
**If the front driveshaft does not turn, the transfer case is locking properly and we need to continue searching.
Step 4) With the front wheels in the air, engine idling in PARK, spin one front wheel. The other wheel should spin the opposite direction. If it does, the system should be properly engaged. Safely lower the vehicle to the ground and take it for a test drive. If the wheels do NOT spin in opposite directions, there is a problem with the front differential or axle. Start a new thread with the results of your checks, and we'll go from there.


Keep us updated.

Hi, depending on the vehicle, there can be different controls. Standard control, 4hi, use in slippery conditions, never on dry pavement. Just push the button, and it will engage. 4low is for extreme conditons and the transmission must be in neuteral to engage 4lo. If you have auto 4wd button, just press the button in slippery conditions. If you have a denali, it is all wheel drive, and there are no buttons to push. So, depending on the model, there are multiple ways, but pushing the button engages it. Good luck...Goop

Good Evening. 4high is a simple deal to get working. 4low has a few more steps. First of course is starting the truck, shifting down into neutral at a stop then put it in 4low. After doing so then put it down in drive 4low should now be engaged. And to take it back out of 4low simply reverse the operation. Any other questions let me know, becuase if it can do 4high the shifting motor can do 4low.

i had the same issue change push button cluster