Skip the auto shop - Our mechanics make house calls

Q: 4x4 issues

asked by on

When I shift from 2wd to 4wd the screen says 4x4 shift in progress then 3 seconds later a wrench appears and says check 4x4 and it doesn't engage. The vacuum solenoid keeps constant vacuum and when shifted into 4x4 there should be no vacuum. I replaced the solenoid and it's still doing it.

My car has 88000 miles.
My car has an automatic transmission.

Hello and thanks for your question. When you shift from 2WD to 4WD the vacuum solenoid is to help switch the transfer case from 2WD to 4WD a slow to no speed. If you changed the vacuum solenoid and nothing changed, try checking the vacuum hose from the engine to the solenoid to see if there are any leaks.

If there is solid vacuum on the hose to the solenoid, then the switch motor on the outside of the transfer case could be failing. Try tapping on the switch motor and then retest. If the transfer case kicks into 4WD, then the switch motor needs to be replaced. If the transfer case still does not go into 4WD, then check the harness to the motor and make sure that the harness is not burnt or corroded.

Check the fuse box for the fuse that controls the motor and see if the fuse is burned. If you checked all everything on your 4WD, you could have a motor that is stuck, a chain could be broken inside the transfer case, or the clutch slider could be damaged inside the transfer case. I recommend checking the switch motor and if it doesn’t work then replace it. If you need help troubleshooting your transfer case, have a certified mechanic, like one from YourMechanic, inspect the shifting problem and advise you on a repair.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: My Yukon Denali is AWD. With front tires off the ground, should the drive shaft and both tires spin freely of each other?

Hi there, thanks for writing in. I'd be happy to help. This is a normal thing. Your front axle carrier has an electronic actuator that locks it in only when the transfer case is locked into 4WD. The fact that...

Q: Passenger side coolant leak

Thanks for writing in about your Ford Taurus. You need to have the cooling system pressure tested to see where it is leaking. From what you've described the water pump may be leaking. The heater core is a suspect as...

Q: Questing about shifting from 4wd to 2wd.

Hi there. When shifting out of 4WD, it is best to stop the vehicle and back up about 10 feet. This will fully disengage the transfer case and put the vehicle into 2WD mode. It is normal for the transfer...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.