U-Box Trailer User Instructions

Get help at myuhaul.com
or call 1-800-528-0355

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Safety alert symbol - This safety alert symbol precedes all the safety messages in these instructions. Safety messages alert you to possible hazards and instruct you on how to avoid or reduce the risk of injury.


READ and FOLLOW all of these instructions and safety messages before operating the trailer. DEATH, DISMEMBERMENT or SERIOUS INJURY to you, your passengers, and others on the road may result if you do not follow these instructions. Make sure all drivers read and understand all these instructions.

See the Connecting Your Trailer section for trailer hook up instructions. A U-Haul representative can assist if you require assistance. Or, for a video go to:

Important trailer towing information

PREVENT WHIPPING by properly loading the trailer. Distribute the cargo weight evenly inside the U-Box container. Loading the trailer heavier in the rear will cause the tow vehicle and trailer “combination” to begin WHIPPING, which is violent and uncontrollable sway.

SIDE to SIDE MOTION (SWAY) THAT BEGINS as you reach a certain speed, will likely become WHIPPING at higher speeds. If you notice sway beginning SLOW DOWN IMMEDIATELY by letting off the gas pedal. Then stop to reload the trailer heavier in the front as soon as possible.

IF WHIPPING or SWAY OCCURS, DO NOT steer, DO NOT apply your brakes, and NEVER speed up. Let off the gas pedal and hold the steering wheel in a straight-ahead position.

A “combination disturbance” is improper handling, whipping, sway, over-steering or other deviation of the tow vehicle or trailer from their intended path, due to one or more causes (improper loading, steering inputs, excessive speed, crosswinds, passing vehicles, rough roads, etc.). IF A COMBINATION DISTURBANCE OCCURS, DO NOT steer or brake. Steering or braking during a disturbance can cause a loss of control or crash.

If a WHEEL GOES off the paved roadway, DO NOT steer sharply and DO NOT brake. Let off the gas pedal and slow down below 25 mph. Then steer gradually back onto the roadway. Proceed with caution entering traffic.

Loading your Combination

NEVER load more than the allowed cargo weight printed on your rental contract, inside the U-Box container when towing with a U-Box Trailer. NEVER exceed the trailer’s maximum gross weight, which is labeled on the trailer. NEVER exceed a lower allowed gross weight and allowed cargo weight as listed on your rental contract.

NEVER overload your tow vehicle. Do not exceed the gross vehicle weight rating (GVWR) and the gross axle weight ratings (GAWR), which are posted on a label inside the driver's door opening.

NEVER load cargo on the outside of the trailer, or extend cargo out the rear of the trailer. Secure all cargo inside trailer. Unsecured cargo may (1) shift and cause dangerous WHIPPING or (2) be ejected and cause a roadway hazard.

NEVER attempt to remove the U-Box container from the trailer yourself. Only authorized U-Haul personnel may remove the U-Box container. If you need the U-Box container removed from the trailer contact a U-Haul Representative.

DO NOT transport hazardous materials, corrosives, explosives or flammables in a U-Box container.

Slow down when towing

AVOID CRASHES by slowing down. Reduce your speed from what you would normally drive without a trailer under similar road conditions. The maximum recommended speed is 55 mph when towing a
U-Haul trailer. Do not exceed any posted speed limit.

DRIVE DEFENSIVELY – anticipate stops, brake early, and never follow closely.

BEFORE GOING DOWNHILL, slow down and shift the transmission into a lower gear. DO NOT RIDE BRAKES on downgrades.

Slow down for curves, adverse weather, hazardous road conditions, road construction and expressway exits.

Before towing and on the road

Use the checklist at the end of these instructions before towing and while on the road.

Make sure your tow vehicle is properly equipped and maintained. Be sure all tires are inflated properly.

ALWAYS wear your seat belt. Be sure children are properly restrained.

DO NOT drive when you are fatigued, sleepy or distracted. Avoid driving at night.

NEVER TEXT while driving. NEVER be distracted by using a cell phone while driving. Distracted driving is a major cause of crashes. If you need to text or use a cell phone, find a safe place to exit the roadway.

NEVER drive under the influence of alcohol or any substance that might impair your vision, judgment or ability to control the vehicle.

NEVER allow passengers to ride in the trailer. Passengers risk injury due to shifting cargo, asphyxiation and lack of collision protection.

No open or soft-top sport utility vehicle is allowed to tow a U-Haul trailer, because in the event of a crash, these vehicles offer less collision and ejection protection.


Your tow vehicle

Your towing vehicle MUST have a curb (empty) weight equal to or greater than the loaded U-Box Trailer weight. Your rental outlet will guide you in selection of an appropriate tow vehicle and your allowed U-Box container cargo weight.

Refer to the owner’s manual, decal instructions or an authorized automotive dealer for any specific handling characteristics of your tow vehicle.

Refer to the owner’s manual, decal instructions or an authorized automotive dealer for any specific handling characteristics of your tow vehicle.

Changes made to your tow vehicle after it was manufactured can affect its ability to tow. These changes can include different tires, suspension changes, etc. Check your owner’s manual or with an authorized automotive dealer to make sure any changes to your tow vehicle are approved. DO NOT tow the trailer if your tow vehicle has changes that are not approved.

Avoid driving on a compact spare tire any longer than necessary. Follow the vehicle manufacturer's instructions.


Maintenance and condition of your tow vehicle’s engine, transmission, steering, suspension, front-end alignment and tires may affect your vehicle’s ability to tow the trailer. Have an authorized repair facility inspect and repair your vehicle BEFORE towing.

To find the towing capabilities of the engine, transmission and axles of your vehicle, refer to the owner’s manual, or check with an authorized dealer. 

Towing equipment requirements

Hitches must be able to tow a loaded U-Box Trailer. A U-Haul representative can advise you on the type of hitch required for your intended use.

Hitch Balls
Hitch-ball sizes of 1-7/8 and 2 inches are acceptable with a U-Haul trailer coupler. A U-Haul representative can advise you on the correct ball size and weight rating for your trailer.  

Other Hitch Systems
Weight distributing or sway control devices ARE NOT USED for towing U-Haul trailers. Towing a properly loaded U-Haul trailer does not require these devices. These devices may have a negative effect on vehicle handling and braking and may restrict the operation of the trailer coupling mechanism.

Lights and Mirrors
When towing a trailer, all lights must be operational. Your tow vehicle may require external mirrors on both sides. A U-Haul representative can advise you of the systems available if your vehicle is not properly equipped.

Loading your tow vehicle

To find how much weight you are allowed to put in your tow vehicle:

Step 1: Find your tow vehicle's GVWR on the label inside the driver's door.

Step 2: Subtract the curb (empty) weight of your tow vehicle from the GVWR. Contact a U-Haul representative for help in finding the curb weight of your tow vehicle.

Step 3: Subtract 400 pounds from the answer in Step 2. This accounts for trailer tongue weight.

The answer in Step 3 is the amount of weight you can put in your tow vehicle. This weight includes driver, passengers, cargo and any additional equipment. If the rear of your tow vehicle seems low, reduce the load in the rear seat, trunk or cargo bed areas. Too much load in the rear can affect handling.

Tire pressure

Set all tires to the proper pressure. Find the recommended COLD pressures on the tire sidewall, owner’s manual, your vehicle’s door decal or on the trailer decal. DO NOT put more pressure in the tire than is indicated on the tire sidewall. Tire pressures go up during driving. DO NOT let off this extra pressure.

Air pressure in the rear tires of some tow vehicles may be increased to accommodate the additional weight of the trailer. Inflate rear tires approximately 6 psi above normal, but do not exceed the pressure limit stamped on tire.

Connecting your trailer

Follow the instructions in this section while hooking up the U-Haul trailer. A U-Haul representative can assist you if you require assistance. Or, for a video go to: youtube.com/uhaulofficialvideos.

Lower the coupler onto the hitch-ball and follow the instructions below to properly fasten the coupler to the hitch-ball. Do not allow your self to become distracted. Ensure that the coupler is properly fastened to the hitch-ball before moving to the next step.


Push down on the latch (C) and fully loosen the hand-wheel (D) by turning counterclockwise.

Lower the coupler (B) onto the hitch-ball (A) as shown.

Check that the ball clamp (E) is positioned below the coupler (B). The coupler should completely cover and enclose the hitch-ball (A).

Hand tighten the coupler by pushing down on the latch (C) while turning the handwheel (D) clockwise. At least 10 complete revolutions of the handwheel are necessary.

When the handwheel becomes tight, move the tow vehicle forward slightly or push rearward on the trailer to ensure that the hitch-ball is properly seated inside the coupler. Recheck that the handwheel is tight.

Check all connections at each stop. Make sure the hitch and hitch-ball are securely attached to your tow vehicle and that the trailer coupler is properly connected to the hitch-ball. Use the checklist at the end of these instructions. If you suspect or detect that something is wrong, contact the nearest U-Haul representative.

Safety chains

The purpose of the safety chains is to keep the trailer connected to your tow vehicle in the unlikely event the coupler comes off the ball or the ball comes off the hitch. Safety chains are attached to the trailer tongue and are equipped with “S”-hooks on their free ends. DO NOT tow the trailer without the safety chains securely attached to the towing vehicle. DO NOT attempt to pull the trailer by the safety chains alone, unless this is necessary to get the combination off the roadway to a safe place.

The left chain (A) crosses underneath the trailer tongue (B) and hooks to the right side of the tow vehicle permanent hitch (C), frame or structure, or to the tow vehicle bumper brackets. Do not attach chains to the ball or to a ball mount that is removable. The right chain hooks to the left side in the same manner. The “S”-hooks (D) can be placed through a link in the chain. Crossing the chains under the tongue allows the minimum amount of slack for turning. Control slack by hooking the chain back to itself or by twisting the links to shorten chain. Be sure the “S”-hooks are secured with a rubber retainer (D).

The chains need slack to allow your vehicle to make turns. Make sure these chains attach securely to your tow vehicle and do not drag on the roadway.

Lighting connections

Make sure all tow vehicle and trailer lights function properly. The connecting wires need slack to allow your tow vehicle to make turns. Do not allow wires to drag on the roadway.

4-Way Flat

If your tow vehicle has a 4-way flat lighting system, connect the trailer lights by plugging into the tow vehicle connection plug. If your tow vehicle does not have a 4-way flat lighting connection system, your
U-Haul representative will be able to instruct you on the connection steps for your vehicle.

Loading the U-Box Trailer

The U-Box Trailer may be loaded or unloaded while attached to your tow vehicle or while disconnected.

Disconnecting the trailer

1. Park the U-Box Trailer on level ground in a straight line with the tow vehicle in park, turn motor off, and set the parking brake.

2. Disconnect safety chains and lighting wiring from the tow vehicle.

3. Loosen handwheel on the coupler, depress latch and rotate handwheel counterclockwise.

4. Pull retaining pin on tongue jack (A) and rotate jack down to vertical position, release pin making sure it is engaged to secure jack vertically. Turn the tongue jack handle (B) to raise the coupler off the ball.

5. Pull tow vehicle forward and away from trailer.

Stabalizing parked trailer

1. Place wheel chocks or a similar wedge under each tire of the parked trailer. Rotate the tongue jack handle to raise or lower the tongue until it is about two inches lower at the front than at the trailer rear.

2. Lower the rear drop-down stabilizers (C) located behind the trailer wheels by removing the cotter pin (D) from the hitch pin (E) and then removing the hitch pin from the stabilizer. Lower the stabilizer and place the pin back into the hole that allows the closest contact to the ground. Place the cotter pin back in the hitch pin. Now lower the rear drop-down stabilizer on the other side of the trailer.

3. Rotate the tongue jack handle to raise the trailer until the stabilizers make contact with the ground. The trailer should now be approximately level.

Failure to follow these loading instructions may result in sway or WHIPPING and lead to total loss of control.

U-Box Trailer

Load your trailer with the cargo weight distributed evenly inside the U-Box Trailer. Do this by loading the heaviest items (such as appliances, toolboxes, boxes of books, etc.) low and in the center of the U-Box container, load your lighter items near the front, rear, sides and top. Pack all items closely and firmly and secure with rope to the tie-downs in the trailer or pack tightly with furniture pads. This will place the proper amount of weight on the hitch (tongue weight). If the trailer is not completely full, secure the load with rope. This will prevent the load from shifting or damaging your belongings. Be sure the cargo door is closed and latched securely.

Secure your load, it’s the law. A U-Haul representative can advise you on the products available to secure and protect your goods.

Tongue weight

This guideline is to help you make sure the trailer is loaded properly by checking the tongue weight. DO NOT disconnect the trailer to do the following.

Step 1: With the tow vehicle and trailer empty, and the trailer attached to your tow vehicle, measure the distance from the ground to the top of the trailer coupler handwheel.

Step 2: With the trailer fully loaded and the tow vehicle empty, measure the distance from the ground to the top of the trailer coupler handwheel.

Step 3: Subtract the answer in Step 2 from the answer in Step 1. (Answer 1 – Answer 2)

If your answer in Step 3 is greater than or equal to 1 inch, your trailer has enough tongue weight. If your answer is less than 1 inch, it is recommended that you reload your trailer, and put more weight in the front of the trailer. An answer less than 1-inch can cause sway or WHIPPING.

Take your combination for a short test-drive. If you feel the combination is not handling properly, reload your trailer. If you are not sure the trailer is properly loaded, get help at myuhaul.com, call Roadside Assistance at 1-800-528-0355 or take your combination to the nearest U-Haul location and ask if your trailer is properly loaded.

Do not overload

NEVER load more cargo weight inside the U-Box container than listed on your rental contract, when towed with a U-Box Trailer. The U-Box Trailer is designed to move household-type goods. Commercial loads (such as wood, food products, machinery, etc.) are heavier than household goods. DO NOT load the trailer more than one-third full if you intend to move these items.

Never load the trailer so that it exceeds the maximum gross weight specified on the certification label. Your rental contract may list a lower ALLOWED cargo weight, based on your specific tow vehicle, never exceed these weights. If in doubt, check the weight at a commercial or state scale. (Search Internet or Yellow Pages under “Public Scales.”)

Hazardous materials

 DO NOT transport hazardous materials, corrosives, explosives or flammables such as gasoline or paint thinner in a U-Box container. A container that is almost empty is just as dangerous as a full one. Flammables may explode or ignite through spontaneous combustion from vehicle movement.

Empty and air out the tanks on lawn mowers, camping stoves and lanterns before loading.

Propane tanks cannot be transported in any U-Box container.

NEVER fill a portable fuel container IN or ON the trailer. Set tanks on the ground to fill to avoid static electricity and prevent sparks.

Securely close and properly package household cleaning products.


As necessary, remove wheel chocks, raise the rear drop-down stabilizers, and stow the tongue jack to horizontal position before towing.

Before towing make sure the retaining strap around the U-Box container is secure and tight. To tighten the strap pull the ratchet release (F) to free the handle and then pull the handle up to ratchet tight. Then push the handle down to lock it in place. Make sure the retaining latch (G) is securely locked in place.

Reduce speed

Slow down for curves, adverse weather, hazardous road conditions, road construction and expressway exits. Do not feel secure because your trailer tows easily at higher speeds. A road hazard that could be avoided at 55 mph, may become unavoidable at a higher speed.

When driving at a lower speed you are less likely to lose control of any vehicle, than when driving at a higher speed. Excessive speed is a major cause of accidents.

U-Haul does not recommend using cruise control or overdrive when towing a trailer.

Stopping and following distance

Your combination is heavier and longer than your vehicle alone. This means it will take you longer to stop.

Allow at least 4 seconds between you and the vehicle in front of you. Start counting when the back of the vehicle in front of you passes a fixed object, such as a line or crack on the road. If the front of your vehicle reaches the object before the end of the 4 seconds, increase your distance.

If you are driving in adverse weather, such as rain, snow, or fog, use at least a 5 second gap.


Whipping is violent and uncontrollable sway caused by loading a trailer heavier in the rear half. Persistent side to side sway motion is not normal. If this occurs at a certain speed, it is a signal that WHIPPING will likely occur if speed is increased by a small amount. If you notice this behavior immediately slow down and maintain at least 10 mph below the speed this sway was first noticed. Then stop at the first opportunity and reload the trailer heavier in the front half to correct this problem. See next section.

Combination disturbances

A “combination disturbance” is improper handling, whipping, sway, over-steering or other deviation of the tow vehicle or trailer from their intended path, due to one or more causes (improper loading, steering inputs, excessive speed, cross winds, passing vehicles, rough roads, etc). 

If a combination disturbance occurs:

Let off the gas pedal. NEVER speed up to try to control a combination disturbance.

DO NOT apply your brakes.

HOLD THE STEERING WHEEL in a straight-ahead position. DO NOT try to control the combination disturbance by turning the steering wheel.

After a combination disturbance has stopped:

Pull a safe distance off the roadway and stop. Get all occupants out of the vehicle and away from the roadway.

Check the cargo in the trailer to make sure the load has not shifted. Make sure the U-Box Trailer is loaded evenly.

Check that all the tires are properly inflated and that all lug nuts are tight.

Check the trunk or rear cargo area of the towing vehicle to make sure it is not overloaded.

REDUCE SPEED to 55 mph or LESS. Combination disturbances happen most often at higher speeds.

If the combination disturbance persists, contact the nearest U-Haul representative and have them inspect or exchange the trailer. If the combination disturbance still occurs, something is wrong with your tow vehicle.


Your combination is heavier and longer than your tow vehicle alone, and will require more time and distance to pass.

Passing by another vehicle in the same or opposite direction can result in a combination disturbance. See the Combination Disturbances Section for what to do if this happens.


SLOW DOWN BEFORE starting down hill. Shift into lower gear and let off the gas pedal, this allows the engine to help you control your speed. Combination disturbances happen more frequently going downhill and at higher speeds.

DO NOT ride the brake pedal going downhill. Prolonged use of your brakes results in overheating and possible loss of braking. When you need to slow down, apply the brake pedal and slow down below the intended speed. Then let off the brake pedal completely. Repeat as needed.

Shift into lower gear to prevent your tow vehicle from jerking due to engine lugging when traveling up hills. This will improve gas mileage and reduce engine overheating.

Road shoulders

If a wheel goes off the paved roadway:

DO NOT turn the steering wheel sharply.

DO NOT apply your brakes.

Let off the gas pedal and slow down below 25 mph. Then steer gradually back on the roadway. Proceed with caution entering traffic.

Sometimes the trailer is wider than the tow vehicle. Allow for this by driving in the center of your lane.

Sharp corners

Avoid turning too sharp on corners, in gas stations or parking lots. Because the combination is longer the trailer will track inside the turn and may sideswipe a vehicle or object. Drive slightly past the corner before turning or turn wider than you would with a car to avoid this. Or simply plan ahead and avoid sharp turns where you can.

Backing up

Keep your hand at the bottom of the steering wheel. To move the trailer left, move your hand left. To move the trailer right, move your hand right. If your combination starts to jackknife, or isn’t headed where you want it, STOP. Pull forward to straighten out, then start again.

Get help to watch as you are backing. If you cannot get help, exit your vehicle and make sure there are no people or obstructions in the way.


Immediately park your combination in a safe place, completely off the roadway. Turn on your emergency flashers. Get all occupants out of the vehicle and away from the roadway.

If you must continue on the roadway to reach a safe place off the road, turn on your emergency flashers and proceed with caution.

If necessary, drive on a flat tire to reach a safe place completely off the roadway. Drive slowly.

If the trailer's mechanical problem is minor and the combination can be safely driven, proceed to the nearest U-Haul location, get help at myuhaul.com or call Roadside Assistance at 1-800-528-0355.

If the mechanical problem is major or if the trailer is inoperable or cannot be driven safely, get help at myuhaul.com or call Roadside Assistance at 1-800-528-0355. Be prepared to give your exact location and a callback telephone number. Have your contract with you when you call. They will have a U-Haul representative contact you and do whatever is necessary.


In case of an accident, get everyone out of the vehicle and completely off the roadway. Call an ambulance if anyone is injured. Notify the police as soon as possible and then report the accident at myuhaul.com or call Roadside Assistance at 1-800-528-0355.

Towing checklist

(Use at each stop)

Before towing

  • Towing hitch and hitch-ball are tight.
  • Coupler handwheel is tight.
  • Safety chains are properly attached and secure.
  • All lights are connected and working.
  • Tongue jack stowed and rear stabilizers raised.
  • Check all tires for correct pressure.
  • Load U-Box Trailer evenly.
  • Secure the load.

Before driving

  • Fasten seat belts.
  • Adjust mirrors.

On the road

  • Reduce speed to 55 mph or below.
  • Stop often for rest.
  • Inspect your vehicle and trailer connections at each stop.
  • Anticipate stops, brake early.

Remember - crashes are caused by

Driver error or inattention.

Excessive speed.

Failure to load the U-Box Trailer evenly.

You should always

Load U-Box Trailer evenly.

Reduce your normal driving speed.

Wear your seat belt.

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