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What does a Jeep Transfer Case do? (FAQs)

What does a Jeep Transfer Case do? (FAQs)

Jeeps are one of the United States’ most popular vehicle manufacturers and for a good reason. They are well-built, stay up-to-date on technological advances, and have excellent overall performance. One common question surrounding Jeep is, what does a transfer case do?

The short answer: A Jeep transfer case feeds power to the Jeep’s front and rear drive shafts, which in turn delivers the power necessary to use all four wheels at once, known as four-wheel drive, so long as your vehicle comes equipped with various lockers. Gears in the transfer case are then operated while rotating the rear drive shaft. 

This article will discuss what exactly a transfer case does in Jeep vehicles, such as their Wrangler models. So keep reading! We have everything you need to know about the transfer case in a Jeep.

Jeep Transfer Case Defined

Jeep is a well-known, homegrown vehicle manufacturing company based in the United States and is known for its excellent and tough all-terrain vehicles. Even though numerous cars are in the same niche, Jeep has remained at the top of this market for decades. 

One of the most popular models produced by Jeep is its Wrangler; Jeep is often considered the company that took four-wheel driving to where it is today, which is shown off by its various Wrangler models.

Jeep Wranglers are known for being part-time four-wheel drive vehicles, which means you can switch between two-wheel drive and the latter. A transfer case is what allows this function to take place and gives the driver the ability to control various wheel powering options. 

If you’re not well versed in car mechanics and jargon, you may be wondering what a Transfer Case is and why it is essential to Jeep’s four-wheel drive function. 

What Exactly Is A Transfer Case?

You may have heard the term transfer case from time to time when discussing off-road and four-wheel drive vehicles. But what exactly does it mean? In simplistic terms, a transfer case is a mechanical component of the vehicle that allows the driver to change to four-wheel drive. 

This is accomplished because the Jeep can share power between the rear and front wheels when you turn on the four-wheel drive control. During this, you can opt for HI or Lo, which is often determined by the scenario you find yourself in. Various places you end up may require more torque while using the four-wheel drive. 

How Does A Transfer Case Work In A Jeep?

If you are curious about the transfer case in your Jeep Wrangler, you may also want to know exactly how it works. While it’s a mechanical device that often requires a lot of vehicle jargon to understand, we will try our best to explain it in simplistic terms below.

Available Jeep transfer cases –

In reality, the transfer case contained within your Jeep works by delivering power to both your front and rear drive shafts, which then spreads this power to all of your Jeeps tires, so long as your Jeep comes with lockers, i.e., the ability to lock the axles together. 

The power supplied by the engine will then feed your Wrangler’s transmission; this will control the gears contained within the transfer case, which in turn rotates your vehicle’s rear drive shaft as you drive. 

If you were to look inside your transfer case, you would see a chain link device or gears which control the vehicle’s rear-drive shift and the gears for your vehicle’s front drive shaft.

History Behind Four-Wheel Drive And The Transfer Case

Ferdinand Porsche was one of the first people to engineer and produce a vehicle that was capable of four-wheel drive. Following this, he would establish the world-renowned Porsche vehicle company.

Ferdinand created a four-wheel drive made up of electrical motors strategically positioned on each wheel, powered by a simple gas generator. 

However, the first transfer case was not created for a few years until 1902, when Jacobus Spyker, a Dutch company, produced a mechanical version that used a transfer case to alternate the power between the front and rear of the tires of the vehicle. 

Using A Transfer Case Car Off-Road

If you decide to enable the four-wheel drive option in your Jeep Wrangler, what you’re essentially doing is activating the mechanical component of the transfer case. In your Wrangler’s normal drive mode, your engine will feed power to the transmission. 

As your transmission receives power, it passes this onto the vehicle’s driveline spine, which ultimately powers the rear drive shaft resulting in the drive power of the rear wheels. If you decide to engage your Wrangler’s four-wheel drive, the vehicle’s selector arm will shift a spline coupler in order to force its engagement to the spline gear.

What all this jargon means in simple terms is that once the spline coupler engages the gear, it uses the chain we mentioned previously, or a set of gears, to provide power to the front wheel drive shaft, allowing both the rear and front wheel shaft to work at once; thus, your Jeep has four-wheel drive.

As you switch your vehicle to four-wheel drive, you automatically end up in the HI mode, which is often referred to as the one-one gear ratio. If you’re on some dirt roads or a rough trail and require additional power or torque, you may need to switch to the LO mode to get yourself out of a tricky situation. 

As you transfer your four-wheel drive from HI to LO, this will restrict the Jeep to around one-third of its regular speed, but it will also increase the vehicle’s torque by one-third. So the LO mode is generally only ever used when you’re in a tough situation. 

Transfer Case Maintenance 

Just like every other mechanical component in your Jeep, the transfer case must be kept in working order to ensure that the vehicle performs to the best of its ability. This means that maintenance must be performed from time to time. 

You should aim to change the fluid contained within your transfer case every 25,000 to 30,000 miles to ensure it stays in optimal shape. It’s also recommended that if you have recently crossed any deep water, you drain and replace the fluid contained within your transfer case. 

Draining the fluid from your transfer case is a relatively simple task and can be performed at home if you’re willing to get your hands dirty. Simply drain out the fluid and refill it with an oil such as Mopar ATF Fluid 4. Usually, around two quarts is the perfect amount. 

If this maintenance is performed regularly, this will ensure the longevity of your transfer case and will ensure both protection and proper lubrication of the gears contained within the transfer case. 

How Do I Know If the Jeep Transfer Case Is Faulty?

Just like all mechanical components of a vehicle, the transfer case can start to fault from time to time. While they are supposed to last as long as the vehicle, you may have to take them in to get fixed under certain circumstances. We will list a few of the most common symptoms of a bad transfer case. 

It’s Hard To Stay In Four-Wheel Drive

If your begin to notice that your Jeep’s transfer case keeps taking you out of four-wheel drive, it could indicate that there’s an external problem with your driveshaft or differential, in this scenario, its often hard to diagnose the problem, so its best to take it to a professional for a proper diagnosis. 

You’re Having Shifting Issues

One of the most common symptoms of a faulty or bad transfer case is when you begin to notice trouble as you try to shift between your gear ranges. While this problem may stem from low fluid levels or even a damaged linkage, it generally occurs from an internal transfer case problem. 

Before you begin to panic, you should always have a quick look at the manual just in case it’s a simple problem stemming from something like trying to switch to a four-wheel drive from neutral. 

A Puddle Of Fluid Under The Transfer Case

If you notice a puddle of fluid directly under the transfer case area, then this is a sure sign that there’s a leak somewhere and that your transfer case may be the problem behind some of your vehicles’ recent malfunctioning. 

You’ll want to ensure that the leak is definitely coming from the transfer case by either lifting your vehicle and inspecting it or taking it to your local mechanic to do so for you. The leak should be easy to identify and should be coming from the transaxle assembly of the rear of the transmission.


Your Four-Wheel Drive Won’t Engage

If you notice that your Jeep will not enter into four-wheel drive, then this can generally be traced back to a transfer case problem. However, it doesn’t necessarily mean so; it could arise from an electrical fault or even a faulty shift mechanism on your vehicle’s front axle. 

My Closing Thoughts

So, now you know that the transfer case in your Jeep is the mechanical component that allows you to drive in four-wheel drive. Ensure that you keep up your regular maintenance on the transfer case, as this will ensure your Jeep performs at its optimal performance when in four-wheel drive. 


Up Next:

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