First drive: Tesla's all-electric Roadster

First drive: Tesla's all-electric Roadster

The original two-speed Tesla transmission has had notorious reliability issues, in the end forcing the company to sell the car with the unit effectively locked in second gear. That was a temporary solution, however, and now that the California company has partnered with Borg Warner for production of its single-speed Powertrain 1.5 gearbox, the company is ready to begin rolling them out to new and existing vehicles.

Along with the new gearbox comes a range of motor and power improvements as well. Since the BorgWarner unit is capable of handling more torque, specifications are increased from 211lb-ft (286Nm) to 280lb-ft (380Nm). The power boost allows the car to cruise another 23mi (37km) on a single charge according to the EPA, raising the rating to 244mi (390km), approaching the range of a conventional-fuel-powered vehicle.

As Tesla said when it decided to move forward with production of the vehicles despite the problematic first-generation gearbox, the new updates will be free to existing owners.

The company hopes the new gearbox will help it reach a higher volume of production, ramping up from the current 10 vehicles per week to 40 per week by early next year. "Successfully implementing the new gearbox in less than a year was an incredible technical challenge and huge accomplishment for Tesla's engineers," said Ze'ev Drori, Chief Executive Officer of Tesla Motors.

At the moment about 50 Tesla Roadsters with the preliminary drivetrain have been delivered or are in the process of being built, so the retrofitting process shouldn't be the logistical nightmare it would be if the car had sold thousands of units already.

New performance figures for the revised powertrain are yet to be revealed, but with a power increase approaching 25% and a more robust drivetrain, the improvement should put the car much closer to its original claimed figures of 3.9 seconds 0-60mph.