4WD, a common abbreviation of four-wheel-drive, is common in trucks and SUVs, but can you turn while your car is in 4WD?
Turning while in 4WD will cause the transfer case, front axles, and rear axels to bind up. While you are turning, switch to 2WD, then switch back to 4WD if needed after the turn is completed. Never turn in 4WD while on dry pavement, or while in areas where the wheels have good traction.
If you do choose to turn while in 4WD, the car can make many worrying noises.
Why You Should Never Turn in 4WD
While driving, it is almost impossible to avoid turning. However, you should only turn while in 2WD, and never in 4WD. When you are turning, the swiveling of the front wheels creates a wider turning circle than the rear wheels and this causes a difference in the rotational speeds of the front and rear wheels. This in turn causes a difference in speeds of the front and rear propeller shafts, otherwise known as drive shafts. source
Since there is a difference of speed between the inner and outer wheels, both axle shafts turn at different speeds. If you turn while in 4WD, this can make the inner workings of the axles become worn out more quickly than they should. Differences in speed can also be caused from uneven tire ware between the front and rear wheels or varied inflation pressures. source
If you feel like your tires are dragging while you are in 4Wd, it is not an issue with your 4WD system. The drag of your tire “may be a sign of a worn tire, bad alignment, or fault in your braking system. This fault could be a sticking caliper or an emergency brake being engaged when it should not be.” source
Why Turning Locks Up While in 4WD
It is always worrying when the steering locks up while you are driving, but it is especially worrying if it locks up while you are turning. Most of the time if you turn while in 4WD, your wheels should not lock up. However, it does happen. “This phenomenon is caused by the front wheels battling the rotational force coming from the front drive shaft as it tries to slow down the front wheels, causing the massive under-steer effect.” source
“The differences of the relative speeds of front and rear axle which occurs when turning left or right are solved by the fitment of a third differential inside the transfer box. The 3rd differential allows the front and rear propeller or drive shafts to rotate at different speeds while sending equal torque. The 3rd differential or center differential can be locked by the driver when low range is selected or 4H is engaged by the driver which locks the front and rear differentials together.” source
The steering locks up while turning in 4WD because of the different speeds that the wheels move in, and because turning in 4WD causes axel binding. It also locks up because the gears can become jammed because of the different speeds of the wheels.
If you are in 2WD and your steering locks up, it may be caused by an issue with the power steering fluid or the power steering belt. If this occurs, take your vehicle to a trusted mechanic.
What the Worrying Noises Might Mean
Grinding is never a good thing to hear while you are driving your car, but it is even more worrisome when you hear it while you are turning. When you hear a grinding sound when turning in 4 wheel drive means you are experiencing “drivetrain binding. Binding of the drivetrain transfers high levels of torque through the drivetrain and transfer case resulting in difficulty turning, grinding noises, and wheel hop.” source
“Binding of the drivetrain transfers high levels of torque through the drivetrain and transfer case resulting in difficulty turning, grinding noises and wheel hop.” source This is partially caused by the different speeds of the wheels while they are turning, but it can be caused by other things.
The loud clunking sound can also emanate from your transmission when you engage 4-wheel drive on the fly while doing over a certain speed. That speed changes depending on the type of the vehicle and how old the car is. The clunking noise is caused by the gears inside the transmission case as they engage to lock the front and rear drive-shafts. source
The clunking sound that you hear while turning may also be caused by a CV joint failure. A CV joint failure is caused when the protective boot cracks, tears, or becomes damaged. source
If you have turned off 4WD and are turning in 2WD, and your car is still making a grinding or clunking noise while you are driving or turning, take the car to a trusted mechanic and have it looked at immediately.
Why Car Jerks While Turning in 4WD
It is always concerning when your car suddenly jerks while you are driving it, but it is especially worrying when it occurs while you are turning. When 4WD is engaged, then the transfer case joins the front and rear axles and transmits equal power to the front and rear drive shafts. The drive is transmitted through both the front and rear axle assemblies.
“With both part time 4WD and AWD vehicles, once the center differential-lock is engaged and the front and rear drive-shafts are connected inside the transfer box, the difference in their speeds cannot be absorbed inside the transmission. This torsional stress can cause axle binding , ‘drive-line binding’ or ‘drive-line wind up’. This makes turning in 4WD extremely difficult and what causes the jerking effect.” source
If your car becomes jerky while it is in 4WD, your vehicle has begun to under-steer heavily. When this happens, gears often become jammed and makes steering very difficult and even jerky. “This phenomenon is caused by the front wheels battling the rotational force coming from the front drive shaft as it tries to slow down the front wheels, causing the massive under-steer effect. You should avoid engaging 4WD on a high traction surface at all costs. The longer you drive in that mode, you risk serious damage to your drive-train components and you will find it increasingly difficult to remove it from 4WD mode and switch back to 2WD mode.” source
When to Use 4WD
You should only use 4WD when the tires can slip and slide a little. source Use it in situations like when you are in ice, snow, sand, or mud. 4WD has two settings; 4Hi and 4LO.
4Hi is best for when you are trying to get through a situation, not out of one. “This setting is for optimizing traction at the cost of power. Use it when you’re dealing with slippery conditions on otherwise good roads, such as ice or rain. 4Hi should never be used below 15 mph.” source
Use the 4Hi setting when you are on slippery surfaces and driving at street or highway speeds, or when you are stuck in mud, ice, or snow. source
Use the 4LO setting when you:
- need more torque (power) for heavy pulling at slow speeds.
- are climbing steep grades at slow speeds and need extra power.
- are descending steep hills with a heavy load-the low gearing provides engine braking assistance.
- are in very rough terrain
- are in thick mud
- are in heavy snow
- are fording a river
Never go over 40 miles per hour while in the 4LO setting. Switch to the 4HI setting or go into 2WD. Don’t use the 4LO setting to get unstuck in mud and snow. The extra torque will cause the tires to spin, and you will not go anywhere. You will just become more stuck, and will eventually need someone to push you out.
When NOT to Use 4WD
2WD should be used more frequently than 4WD. 4WD uses more gasoline than 2WD, and 4WD should only be used when you are in areas where the tires of your vehicle have very little traction. If you use 4WD on dry roads or pavement, you will cause the transfer case and front and rear axles to bind up, and you will not go anywhere.
Never use 4WD while your vehicle is on dry pavement or asphalt. Most of the time while it is raining or you are driving on wet roads, you do not need to use 4WD, 2WD will give you enough traction to drive safely. If you are driving on wet roads, only use 4WD while you are driving on flooded roads.
“Driving a part-time 4WD system on dry pavement can break the front axles, shear the differential gears, and even break apart the differential case. As soon as you hit dry pavement, shift back into 2WD.” source
4WD is not meant to be used all of the time. If you are going off-roading or into an area where you feel that it will give you the traction that you need to get out of slippery area, then feel free to use it. But you should only use 4WD when you need to. It is a backup system used to make sure that people can always be safe, and is not meant to be used on paved roads or in areas where your vehicle’s tires have enough traction to move your vehicle safely.