A 4WD is your go-to car if you are looking for excellent off-road driving capability. It gives you more power, and it drives better on icy roads and slippery tracks, compared to a 2WD model. And another cool thing… with a 4WD, you can go and crawl over those steep rocky outcrops and gorges.
The thrill of driving a 4WD is irresistible, but if you only have a 2WD, one question that might cross your mind is, “can it be converted into a 4WD?”
The next question you will probably ask is, “how much will it cost to turn a 2WD into a 4WD?” To help you understand the process of turning 2WD to 4WD, I’ve prepared this detailed guide for you.
So, keep reading, and let’s get into the details of 2WD to 4WD conversions.
2WD to 4WD Conversion: Is it Possible?
Yes, it is possible, but it’s not an easy task. You can strip down the 2WD in your car and install a 4WD system. To do this, you will require a number of 4X4 vehicle parts, including the front axle (assuming the car was a rear-wheel drive) and front driveshaft. Then, the parts must be installed correctly.
Another important thing you will need to change is the transmission system of the car. To turn your 2WD into a 4WD, the master cylinder, steering box, and springs will also need to be upgraded. Let’s put it simply: most parts in your 2WD were designed to work in a 2WD system and will require changing so that the vehicle will not only look like a 4WD but will operate like one.
Another crucial thing for the process is getting a qualified welder, probably one who has handled such transformation before. This guy will help get the front axle in position for good performance.
As you can see, 2WD to 4WD conversions are not trial-and-error types of jobs. Therefore, it will be a good idea to have professionals do the job if you have decided to proceed.
Converting a 2WD to a 4WD: The Big Upgrade
The process starts with making a big decision. Well, this is never easy, and most mechanics will tell you that converting the car into a 4WD is an expensive undertaking, and it is better to think of an alternative, such as acquiring a brand new 4X4.
However, if you have a lot of attachment to the car—you know… sentimental value—conversion will be a great way to go.
So, let’s look at the great transformation, starting with the parts.
What Parts Are Required?
As I have already mentioned, this is a major project that requires a lot of expertise, tools, and parts. When it comes to parts, there is a long list of what you need, with some requiring modification to work as expected.
If you can get a donor truck where the parts can be sourced, that would be perfect. But some parts will still need to be bought.
Lucky enough, some auto manufacturers are now selling transformation kits, although these mainly work for car models that are designed to support easy transformation from 2WD to 4WD.
Here are some of the parts that will be required:
- Independent front suspension system. You have to select this system carefully because the front wheels work with many components, from the steering system to stabilizer arms.
- A transfer case and gear shifter system
- Wiring harness for a 4×4 car
- Front axle U-bolts
- Dual shock brackets
- A 4x4drive train
- Front and rear wheel drive shafts (unless the car is a rear-wheel drive already)
- Transmission tail shaft/output shaft.
- 4×4 brake lines.
- Upgraded suspension to accommodate more components plus weight.
With these components, plus an expert mechanic to guide the process, it is time to start the big transformation. You will also need assistant mechanics and support technicians to get the job started.
Adding the Transfer Box to the 2WD Drive
A transfer case is the most defining device on a 4WD vehicle. It receives power from the engine and then transmits it to the front and rear axles through drive shafts. It also plays an important role in synchronizing the rotation of the rear and front wheels.
Furthermore, it makes it possible for the driver to select whether to run on two or all four wheels. Therefore, you will need to start by installing the transfer case on your 2WD.
To add the transfer case, you should be able to marry it with the current transmission system. In most cases, mechanics recommend swapping the entire transmission system as opposed to modifying the box trying to fix new transmission components.
The transmission system should be positioned correctly to ensure that the shafts will reach the front and rear axle correctly.
While still at the transfer box, it is crucial to think about transmission system interaction with the driver. The expectation is that the gear lever will come exactly at the location of the current one, but this is not guaranteed. Therefore, some modifications might be required, and an experienced welder will be a huge help.
Converting the 2WD Drivetrain to a 4WD
This is perhaps the most important stage of the vehicle conversion. So, let’s start by looking at how the drivetrain works. See the images of two main drive trains, first for a 2-wheel drive and second for the 4-wheel drive.
Your vehicle’s drivetrain includes all the crucial components that help to transfer power from the engine to the wheels. As the engine runs, the drive train, through a network of gears and shafts, transmits torque to the wheels to get the vehicle moving. In this case, you are removing the 2WD drivetrain and installing a 4WD drivetrain. Instead of thinking of individual parts of the drivetrain, it will be better to grab the entire thing, if possible.
So, you might want to talk to a salvage car dealer to identify a vehicle that has been written off, but the 4WD drivetrain is okay. Insurance firms might provide a good lead for such vehicles because they usually compensate vehicle owners with new cars or cash and are left with the damaged cars for salvage. Here, your mechanic will come in handy:
- Uninstalling the current 2WD drivetrain on your car
- Identifying the drive train that will work well from the salvage car or garages
- Removing the drivetrain from the donor vehicle ready for installation into your car
As you grab the new 4WD drivetrain, note the additional weight that will go to the belly of your car. Therefore, your car will need to haul this together with its ordinary weight.
Upgrading the Suspension to Handle 4WD
Apart from being capable of generating ample power, the suspension of the car will need to be upgraded to support the additional weight and space for shafts. This means changing the shocks, rear dampers, and leaf packs.
So, let take a closer look at one of them, the shocks:
If you take a closer look at most shocks used on 2WD and 4WD vehicles, they might look similar, but they are rated differently. For example, you might get a 2WD Ram and a 4WD Ram 2500. A closer look will reveal that the four-wheel shocks, especially for the front suspension, are longer for increased 4WD situations.
Again, most of them are structurally different, meaning that you might require some modifications. For example, check the shocks below, one for a 2WD and the other for a 4WD, and then note the remarkable differences. 
The lovely thing about suspensions is that you can simply follow the recommended shock sizes, nut tensioning, weight limits for optimal performance. Although you can trust your mechanics about this because they are the experts, go ahead and ask questions to be sure everything is done to perfection.
Adding 4WD Differentials
If you check the axles of a 4WD drive, each of them has one differential. However, a 2WD car that runs on rear wheels only has one.
If the car is a front-wheel-drive model, the differential will not be visible because it is housed in a transaxle. A differential is part of a car’s rear or front axle assembly and it plays a key role in helping the wheels spin at different speeds for proportionality. Read our post about the importance of a front differential in a 4×4 to know more about it.
When negotiating a corner, the wheels on the outer side rotate at a faster rate to cover a longer distance compared to the inner ones so that the vehicle does not skid. This proportional revolutions per minute (RPMs) for different wheels are made possible by the axles.
If you get a differential with Diff-lock, it will be possible to make the wheels rotate at the same speed, which is necessary to get the car out of mud or through rocky trails without getting towed.
When you install the differential, it should be fitted to the transfer case so that it can receive torque from the engine to rotate the wheels. Here, you will need to factor the measurements between the transfer case and differentials carefully. Also, you have to give enough room for shaft misalignment for smooth operations.
One crucial thing about differentials is that they need proper oiling for the network of bearings to work effectively. Therefore, have the differential checked for possible damages, especially if it is from a donor vehicle. Again, it should be oiled properly for free bearing movement.
Time to Get the Torque Right: 2WD vs 4WD Engine Power
When it comes to power, we need to demystify one common myth that people usually associate with 2WD to 4WD conversions: vehicles lose power after transformation.
This is not true if the transformation—especially the installation of the transfer case, drive train, and differentials— is done correctly. The main reason why cars that are converted from 2WD to 4WD depict lower power is that the engine power has to deal with additional weight and duties, including carrying the drivetrain and differentials.
Also, the additional height and larger wheels are likely to increase drag, resulting in suboptimal performance. Therefore, the car’s 2WD conversion to 4WD should include additional procedures to boost the engine power.
Here are some good considerations for boosting your car’s engine power:
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Installing a High-Flow Air Filter and Intake
A quick and easy way to boost your car’s horsepower is by swapping the air filter for a high-performance one. This can help the engine breathe better and deliver more torque.
Remember to check carefully to ensure that only the filters allowed in your state are bought and used for car transformation.
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Install a Supercharger
A supercharger is designed to help draw in more compressed air to mix with fuel before combustion in the engine. The effect will be more combustion and energy for your modified 4WD. Because superchargers are belt-driven, they are very effective since they do not require an intercooler to operate. Therefore, your vehicle will have fewer heat-related issues.
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Use a Performance Camshaft
Another awesome method of increasing power and torque for your “4WD” vehicle is installing a performance camshaft to help enhance the timing and duration of valve opening. This can help to increase both power and acceleration. However, this method has one notable downside: the engine is likely to become noisier, especially when idling.
How Much Does a 2WD to 4WD Conversion Cost?
Now, onto the big queries: “what is the cost of converting a 2WD to a 4WD?” and “is it worth the effort?”
Needless to say, the process of converting your two-wheel drive into a four-wheel drive is expensive and complex. However, it might not be that expensive, especially if you have a donor 4WD car where all the parts will be sourced.
The main challenge starts when you need to do a complete reassembly of the 4WD frame, especially the complicated transmission system. In such a case, there are so many components to change.
Also, the vehicle brakes that you were used to when driving a 2WD will need to go. A new braking system is never cheap. The actual cost of the replacement parts and different systems will vary depending on the nature of the 4WD that you are working on.
When it comes to labor costs, vehicle conversions are never cheap. Many experts charge between $2,500 and $15,000 for the job.
When calculating the cost, you should not stop at the price of different parts and labor. Consider that as the base cost. In addition, you need to include the following costs:
- The cost of testing your car
- Insurance costs, which might be relatively higher compared to other OED models
- Possible need for more regular repairs of your converted 4WD
One More Thing!
As you embark on the transformation process, it is important to appreciate that, unlike new cars that come with a manufacturer’s warranty, you’re pretty much on your own with your newly transformed car.
Even the individual part sellers may not be willing to guarantee the quality of the products used during the transformation—for lack of standards. For example, if you buy a shock with a specific rating, it might be difficult to prove that it was subjected to the recommended weight levels.
Therefore, here are a few things that you need to do:
- Make sure the vehicle is tested well to confirm that all systems are running as expected.
- Develop a good maintenance schedule for the car and strictly follow it to keep your vehicle in top condition.
- Before your converted vehicle goes on the road, make sure it is tested by relevant authorities and given a clean bill of health.
- Ensure the car has the necessary insurance cover before hitting the road after the conversion.
Final Thoughts
Now that you have seen the procedure of converting a 2WD to a 4WD, are you ready for the process? Well, it is expensive and complex and you should only get started after understanding what it entails. Particularly, you need a lot of patience, commitment, and help from expert mechanics to make the process successful. However, converting the car can be exciting because it would make the vehicle stand out and deliver greater attachment. So, if you are not willing to sell the 2WD and purchase a 4WD, the conversion can be a worthwhile project.
