Can You Convert 2WD to 4WD: Adding 4-Wheel Drive To a Truck

So you probably drive a 2-wheel drive truck and most likely not by the means to upgrade to a 4-wheel drive truck so you are considering converting your existing 2WD to a 4WD. I mean how hard can it be right? VERY HARD! and VERY EXPENSIVE! However, with that being said, it definitely can be done, but it is by no means a cheaper option to simply selling and purchasing a used 4-wheel drive of a similar or even slightly newer model. If you want to read about the process and what’s involved with converting a 2WD to a 4WD, continue reading!

Can you convert a 2WD to a 4WD by adding 4-Wheel drive to a truck? Yes, 4WD can be added to a truck that was originally produced with a 2WD drivetrain, especially if the vehicle was also offered in a 4-wheel drive version. The wiring harness, mounting holes and certain brackets might already be in place of the 2WD model, however, there are many other factors such as drivetrain, transfer case, suspension, transmission, electronics, engine power and differentials to take into consideration.

It is Possible

So we’ve established at this point that it is definitely possible. So, the real question we should be asking is not really if it is in fact possible, but rather if it is a financially feasible project. Meaning, will it be a cheaper alternative to say, selling your existing 2WD and purchasing a used 4-Wheel Drive.

Major Project

This is a major project to undertake and you will need plenty of expertise, tools, time, patience, and most importantly money, since this is not a project to be undertaken in a hurry or in anyone’s backyard over a weekend, with a couple of beers and a hammer. Not at all, this is a job for the professionals or somebody with a very strong mechanical engineering background. Oh and did I mention, a huge bank balance…

So let’s dig into it a bit deeper. Let’s entertain the idea for a while and identify as many of the components that will require upgrading, modification, and replacing. We will be as realistic as possible with the required 4-wheel drive components.

Click here for a FREE cost breakdown to convert a 2WD to 4WD

Adding 4 Wheel Drive to a 2WD Truck

There are numerous components, modifications and engineering factors to consider, and I’m going to repeat myself again by saying, you’re better off selling your 2WD and purchasing a used 4WD of a similar year model and make. By far a cheaper option plus you will maintain your sanity.

Lose The Receipts

There are not many examples of people crazy enough to undertake this project but there are a few who have attempted it. This is a project you do not want to count the cost or time or keep the receipts for all components purchased since you will soon realize, you would’ve been better off simply purchasing a used 4WD. That’s not going to bring you joy if you’ve exceeded the cost and the truck still doesn’t run properly. Not a good thought!

Ok ok, enough with the negativity now, let us assume, for entertainment purposes, that you have a blank check and you were given the task of converting a 2WD to a 4WD. All expenses paid, just pull it off. Or you want to build one of those crazy competition trucks with roll-bars, huge spotlights, and massive chunky tires. Well, in that case, you probably will be better off building one from scratch as opposed to buying one.

Donor Truck

Ok, so to make our job a lot easier, note I said easier and not easy, there’s a difference. We will need a donor vehicle of the exact same model as the one we are converting. This you could probably source at a junkyard for a lot cheaper than say purchasing a used one. Because if you purchase a used one, then you already have a 4WD and it negates the need to convert your existing 2WD. whatever

Let’s just start with the donor truck,

New 4WD vs Old 4WD

Selecting the correct year model will mean the difference between a relatively electronic free, purely mechanical build versus a more modern 4WD with electronic sensors and wiring harnesses. These electronic sensors and wiring loom will need to be connected up to ECU’s and other complicated electronic management systems. This means if you’re not experienced in the auto-electrical field, you are going to need to call on the services of an auto-electrician.

The older trucks will require a bit of metal fabrication and some reinforcement to accommodate the leaf spring and solid axle conversion.

Modern vs Old

More modern 4WD trucks are a lot more sophisticated and complex in design. This is since manufacturers are constantly under pressure to develop more user-friendly, greener and safer vehicles. So the modern 4WD will have features like traction control systems, wheel sensors, more electronic wiring, and sophisticated braking systems and in the case of an

IFS vs SFA

IFS (Independent Front suspension) more complex suspension components. So once you manage to get the mechanical side sorted out, you now are faced with the electronic nightmare. You will need lots of customization to get the 4WD to actually function properly. It’s going to be a much easier and cheaper task to stick with a solid front axle setup with leaf packs, instead of the IFS with dampers and springs, lower control arms, stabilizer arms, linkages, ball joints, and the works.

Vehicle Diversification

So if you are going to pull off this project you are better off with manufacturers which are renowned for vehicle diversification. This means they utilize the same chassis, drivetrain and other components in models, types, and ranges. Manufactures do this to cut down on costs to develop separate chassis for a 2WD vs a 4WD or to change the wiring harness to accommodate a specific model. They use the same components and simply blank off the parts that are not needed in the lower-spec models. So that’s a positive thought for our crazy project.

Miscellaneous Parts

Once you have a donor truck you’ll have all the miscellaneous parts that this job would require, so it becomes a simple stripping and fitting process for smaller items. Large manufacturers like Ford, Chevy, Toyota, and Volkswagen, for example, are renowned for doing this.  So if you drive a Ford, Chevy, VW or a Toyota, you are in a slightly better position to convert your existing 2WD to a 4WD with the least amount of hassles.

Certain aftermarket companies actually offer these fabricated packages or kits to allow you to do a DIY conversion, especially If it’s a very popular truck and the bolt-on conversion is simple enough.

So what are some of the components you’ll need to convert your 2WD to 4-Wheel Drive. Let’s have a look. You will require the below but not limited to the following:

  1. A transfer case
  2. Upgrade your transmission tail-shaft / output shaft
  3. Front and rear drive-shafts unless it’s a rear-wheel driven 2WD then only a front driveshaft
  4. A complete Front axle assembly
  5. Transfer case gear shifter
  6. Wiring harness if existing wiring does not include blanked-off 4WD wire connections
  7. Upgrade / new 4×4 compatible transmission
  8. Upgraded suspension to accommodate the extra components and weight
  9. AND MORE…

The more I’m thinking about this idea, the more I realize what a ridiculous exercise this actually is, but be that as it may, let’s continue. The above-mentioned parts list are the basic differences between a 2WD and 4WD and I am sure I’ve missed a ton of other components. That we’ll identify to as we go along.

Let’s next look at the transfer case since this is the core of the modification. You get this to function correctly and we are looking good.

Adding a 4WD Transfer box to a 2WD

The transfer case is the heart and soul of the 4WD and once you get this married up and functioning properly, you’ll be in a good position. What is entailed?

You’ll need to be able to marry the transfer case up with the existing transmission. Here you are better off purchasing or swapping the entire transmission with the transfer case from a donor 4WD truck since the hassle of opening the transmission to modify the box to accommodate the TC will be a headache. Click here to read about converting a 2WD transmission to 4WD.

The transfer case will need to connect the front and rear drive-shafts to the front and rear axles. The drive-shafts will need to be balanced properly.

Converting a 2WD to a 4WD Drivetrain

If the truck you are converting was originally available from the factory in that configuration, then a few trips to the auto salvage yard or a donor would give you the major and miscellaneous parts needed to pull it off.

On the contrary, if the truck you want to butcher was never offered in 4WD configuration, you have a major design and construction project to embark on. The expense, time and expertise to successfully accomplish this will be huge.

Upgrading the 2WD Suspension to handle 4WD

Due to the additional weight being added, the 2WD suspension will require a substantial upgrade. Here we are talking front and rear dampers as well as leaf packs. This alone will be a few thousand out of your pocket. The suspension upgrade is necessary to accommodate the additional weight from the transfer case, drive-shafts, and differentials that have been added.

This excludes the other miscellaneous components that will all add extra weight. By converting the vehicle 2WD to 4WD the weight will increase .and hence the stress on chassis and all parts of the car. So you also have to modify the load bearing capacity of the other parts of the vehicle to bear the stress.

Adding a 4WD Differentials

Opting to go with a solid front axle will be the easiest option here since it negates the need for all the extra components found on an IFS suspension. The front differential will need to marry up with the front driveshaft that connects to the transfer case. Once 4WD is engaged the transfer case engages the front driveshaft to power the front wheels. If the 2WD truck is rear-wheel drive with a rear axle, that eliminates the need for a rear axle.

2WD vs 4WD Engine Power

The additional weight from the added transfer case, diffs, and other components will increase your fuel consumption and decrease engine performance. The 4WD drivetrain has more rotational parts that all add weight thus reducing engine power somewhat. This means you will need to beef-up the engine power to accommodate the extra weight. Aftermarket exhaust, filters, and intake mods are going to be the first upgrades. Later you might want to look at some piston modifications.

Cost

I would suggest you do the math first before embarking on such an elaborate project since the numbers will suggest its not a financially feasible option. You will need to purchase a donor truck or do multiple trips to the junkyard for components. The time, effort and money wasted there alone will indicate its not a good idea.

Also, depending on the make, model and sophistication level in terms of electronics will drastically increase costs. You are probably looking at a starting figure around $3,500 as a starting point. This project could easily run close to the double figures into the thousands if you are going to do it properly.

Resources

Click here for a FREE cost breakdown to convert a 2WD to 4WD

Conclusion

In theory, if the 4WD truck was an older pre 1995 model and 4-wheel drive was a factory option for that model, you have a donor truck so that you had all the miscellaneous parts that this job would require, plus the fabrication skills needed, plenty of time, and a wad of cash you could do it, yes.

Your 2-Wheel Drive is most likely a rear-wheel-drive truck so you will require a new front differential and axle to deliver the power to the front wheels. You’ll need a driveshaft to send power to the axles from the new transfer case. The transfer case needs to be compatible with the transmission to bolt onto it since it functions very different from a 2wd transmission.

Lastly, you’ll need to be able to engage 4WD so you’ll need a shifter, either manually, automatically, or else electronically.

It’s much easier to just buy a 4 x 4 to start with. I think about the only 4 x 4 conversion that might make any sense whatsoever a full-size van since there are kits for doing them.

Jade C.

4-Wheel drives and off-road driving techniques has been my passion for over 20 years. Here we strive to provide the most accurate, up-to-date, information about the functionality, common faults and latest technology built into most 4 Wheel Drives.

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