It might sound like a good idea, but there’s a lot to think about before you swap your automatic transmission for a manual.

Let us paint the scene for you: you’ve just purchased your brand new project sports car, and a vast number of ideas are swirling inside your head about a long list of modifications you just can’t wait to get started on. There’s just one little problem, instead of a true to form manual transmission, your car comes with a slushy and gutless automatic. “Aha, I’ll just swap out the terrible automatic gearbox for a manual one!” you might tell yourself, your head beginning to fill with visions of ripping through the gears as you barrel down the highway.


Well, let us stop you right there because you’re probably setting yourself up for far more work than you realize. There are a plethora of reasons why removing the transmission from your car and replacing it with one that wasn’t made for it is probably the wrong move, some of them are fairly obvious and others not so much.

So before you break out the wrenches and realize you’re way in over your head, let us show you why nine times out of ten, transmission swapping your car, especially from an automatic to a manual is a bad idea.

Related: 10 Unlikely Cars That Were Available With A Manual Transmission

Lots Of Custom Fabrication

Tesla Six Speed Transmission Swap via YouTube

The ease with which we’re used to seeing project cars being built by our favorite automotive influencers gives off the impression that modifying cars is as simple as squeezing a bunch of lego bricks together. Let us tell you, that couldn’t be further from the truth. Cars equipped with automatic transmissions are built from the ground up around the gearbox which came from the factory. Meaning if you want to change it for a manual, all the interior trim pieces, supporting metal frames, and likely the center console will have to be removed, modified, and fitted to accommodate a new manually shifted gearstick.

Tesla Six Speed Transmission Swap 2 via YouTube

Unless you’re very experienced in both metal fabrication and interior trim, the chances of swapping an automatic for a manual transmission while still preserving at least some of the original interior trim is going to be extremely difficult if not outright impossible.


To add to your dilemma, you’d also need to drill holes in the driver side foot-well to accommodate a clutch pedal, sacrificing even more of the car’s interior trim and metal in the process. If any of the custom fabrication connecting the clutch pedal to the transmission is off even slightly, the clutch won’t be able to disengage rendering the car useless, along with most of your interior carpets being destroyed.

Furthermore, there are many cases in which the driveshaft system for an automatic version of a car is completely different than the one used in a manual model. Meaning either spending hours and hours under the car swapping out driveshaft components for ones compatible with your new manual transmission. So even if you do manage to remove your car’s automatic slushbox, install a manual one, fit a clutch pedal and a gearshift all without breaking anything, the interior of your car will no doubt take a pounding in the process. to make matters worse, that’s not even the hardest part of the whole operation.

Related: Honda’s All-New N-One Gets Manual Transmission For Some Stick-Shift Action

Good Luck Reprogramming The Computers

ECU Engine Control Unit Tuning Performance Enhancements Sports Tuner Remapping Performance Chip via

All jokes aside, there are plenty of DIY mechanics whose skills with a wrench are sufficient enough to swap out an automatic transmission for a manual one. Where people generally run right into a brick wall isn’t with any mechanical issues, but rather having to reprogram their car’s computers to accept the input of a manually shifted gearbox. Many modern engine control modules are designed from the ground up around the specifications which came with the car from the factory. Everything from engine idle speed to air to fuel ratios in modern cars is all programmed from the factory based on the automatic transmission the car came with.

via Euro Car Upgrades

Even the most skilled DIY mechanic likely doesn’t have the programming skills to completely rework an ECU management system to the point it works flawlessly with their new manual transmission setup.

To do the job correctly, one would likely need the help of a professional tune shop to dial in the ECU settings to your specifications. To have this done professionally may very well end up costing just as much as the rest of the fabrication you’d managed to do yourself.

With this in mind, if you’re planning on turning your next project car into a manually shifted drift missile, drag strip monster, or canyon carving pocket rocket, chances are you’re better off starting with a car that came with a manual transmission, to begin with. If you still want to see just how difficult it is to do an automatic to manual transmission swap, we recommend watching DonutMedia’s recent video in which they swapped a manual box into an E36 BMW 5 series. When you see all the headaches they ran into, you may think twice about doing it yourself.

Sources: Donut Media

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