top of page

EV Conversion and the Automatic Transmission

EV Manual Transmission | EV Transmission Conversion - Torque Box

Conventional transmissions whether EV manual transmission or EV automatic transmission are designed for internal combustion engines. The multiple gear ratios and ratio spreads work well with the rpm sensitive nature of small gas and diesel engines.

For many years these conventional transmissions were primarily three and four forward speed units and in automatics, of course, incorporated a neutral, park and reverse mode as well.

Over the last two decades, the number of forward speeds has continued to increase in an attempt to squeeze more efficiency out of a less than efficient engine design. As the number of forward speeds has increased (now six, seven, eight, and even ten speeds), the size, weight, complexity and cost have also increased.

Electric car conversions are very weight sensitive and space is always at a premium. Retaining the conventional multi-speed transmission when converting to electric power is very inefficient. ​

EV motors, as a rule, are much higher in efficiency and make their peak torque right from a stop and over a much broader rpm range. This means that all electric car conversions could do very well with a smaller, lighter transmission package. In fact, all class 1 through class 4 vehicles could do well with a single speed reduction gearbox.

Also, brushless DC and all AC motor conversions do not need a reverse gear in the transmission as they can simply turn the motor in the reverse direction to back the vehicle up. As an example, Tesla cars only run a single-speed transmission. This is, of course, true of most all plug-in electric cars.

Torque Trends is addressing the transmission difficulties of those trying to convert their vehicle to electric. The ev-Torque Box is a single-speed reduction gearbox (underdrive) with several ratios available. It is compact, usually less than one third the size and weight of the transmission it replaces. The ev gearbox allows the motor to be placed further back into the transmission tunnel, improving weight distribution and opening up the underhood area for battery, charger and controller placement.

The lower you can get these components in the vehicle, the better the vehicle handles. At approximately 40 lbs., the ev-Torque Box ev gearbox saves between seventy-five to one hundred lbs. The weight savings alone is significant. It’s much more efficient to make your electric car or truck conversion a complete electric vehicle not an electric motor / ICE transmission vehicle.

If you have questions or are ready to order your manual transmission EV or motor/inverter and gearbox package, contact us at 623-755-8214 or reach out to us through our website contact page at

15,801 views0 comments

Recent Posts

See All


bottom of page