By now we are all aware of the sad saga of Tesla Motors and their quest for a reliable two-speed transmission for the battery powered Roadster. After failing to get the necessary durability from the original gearbox supplied by X-Trac, Tesla turned to Magna to try and create a new unit. That obviously didn't work out any better, so they tried to design their own before giving up and revising the motor instead and going to a single speed transmission. Unfortunately Magna apparently didn't take the break-up well and has now resorted to courts for redress.

According to Magna Powertrain's suit against Tesla, they didn't get the money they were owed for the design and development work they did. Interestingly, Magna is claiming that they suggested to Tesla as far back as September 2006 that they should go with a single speed unit, but that path wasn't followed at the time. The suit claims that Tesla had Magna stop work in October 2007 and the Canadian company isn't taking issue with the cancellation of the program. They aren't happy about the fact that Tesla is paying them the $5.6 million they say they are owed for work that was done.

To the best of our knowledge none of Tesla's prospective customers have started litigation yet over the delays and specification changes. If that does happen, things to get ugly for the San Carlos startup. It's not that prospective customers necessarily have a case against Tesla because it appears that Tesla is letting anyone unhappy with what's happening cancel their orders. It's just the distraction and legal costs that could be better spent elsewhere. For Tesla's other legal case, click here.

Update: The filings are public records and the San Mateo Court has them online. You can read them here.

Update 2: Tesla VP Darryl Siry contacted us to clarify the issue with the original X-Trac gearbox. Apparently the problem was not one of actual durability of the transmission itself. Tesla evidently spec'ed out a two speed unit with no clutches. The design intent was to do clutch-less shifting and manage the torque output of the motor during the shifts. Unfortunately the rotational inertia of the motor made this plan unworkable as the torque output couldn't be changed fast enough. According to Siry there were never actually any mechanical failures of the X-Trac transmission, it was simply a matter of Tesla not being able to get their control strategy to work adequately with the hardware. Subsequently Tesla contracted Magna to develop a dual clutch two speed gearbox. Unfortunately, this is the design that had durability issues leading to Tesla's ultimate decision to revise the motor for more power and go with a single speed unit for production. The vehicles running with the interim single speed gearbox are actually using the original X-Trac box with the lower gear locked out (for prototypes) or removed entirely (early production cars). - Sam

[Source: Earth2Tech.com, thanks to Craig for the tip]


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