When you are looking to buy a transfer box to replace your old one it is important to match up the part numbers to be sure it’s the correct one for your car. Get it right the first time – You do not want to purchase the wrong one and then go though the process of finding the correct one all over again.
Before deciding whether to keep a transfer box we look at the history and mileage of the car. We don’t want to keep a transfer box with a high mileage as it may not last a long time. When testing a transfer box we have to check that it engages and disengages four wheel drive like it’s supposed to and that it does it with no problems at all. Some problems with transfer boxes can easily be solved by replacing the fluid so if there is a fault we may decide to do this. We also listen out for any sounds , such as grinding , because that may signal a problem with the transfer box. Once we’ve removed the transfer box we will check it vigorously for damage or rust.
Where to find the Part Number
The part number is either stamped onto the transfer box or on a sticker. Below we will show you an example of where you can find the part number.
How does a Transfer Box Work?
A transfer box is found in 4×4 vehicles and it allows the driver to change how many wheels in the car are moving at one time by moving an additional gear stick. The transfer box has 3 shafts: one which receives power from the transmission , one which sends power to the rear axle and one which sends power to the front axle. The basic options you will have available in a 4×4 are 2WD & 4WD. 2WD is 2 wheel drive and this is when power is sent only to the rear axle , whereas 4WD is 4 wheel drive and this is when power is sent to the front and rear axle. Some cars will have a high and low (Hi & Lo) setting too and this will change the gear ratio , for example 4WD Lo will power both the front and rear axles but the wheels will rotate less but produce more torque.
Types of Transfer Box
Transfer boxes will differ in use depending on the type of car it is in , for example the transfer box in a bigger vehicle will allow the driver to switch between 2 or 4 wheel drive through a lever or selector however , in a sports car there isn’t a selector.
A transfer box will either be gear driven or chain driven. A gear driven transfer box is typically found in larger vehicles and it uses a set of gears to drive the drive shafts. Gear driven transfer boxes tend to be louder and heavier than a chain driven transfer box. A chain driven transfer box uses a chain system to drive one axle , but in some vehicles it will be used for both axles. Usually these are found in compact vehicles & SUVs (Sport Utility Vehicles) , however they’re also used by off-roading enthusiasts as a modification.
A transfer box will either be ‘married’ or ‘divorced / independent’ and this refers to where the transfer box is located on the car . A ‘married’ transfer box is bolted between the transmission’s output shaft and rear or main drive shaft. An ‘independent or divorced’ transfer box is separate from the transmission , typically this type is found on longer commercial vehicles.