Did you see what Elon said about the drive units?
"An analyst from Credit Suisse asked about improvements on Tesla’s drive unit, from a bigger one it initially used to a newer small one. Expecting a boring answer, we got this from CEO Elon Musk instead: “Yeah, right now we’re actually very happy with the quality of the drive units. I mean, internally, our goal — we changed the goal of the drive unit endurance from being approximately 200,000 miles to being
a million miles. Just basically, we want drive units that just never wear out. That’s our goal. And I think we’ve made really good progress in that direction.”
Elon added that the drive units going out now are “excellent,” and then CTO JB Straubel chimed it by adding that they’ve made improvements to the large drive unit. The referenced issues, he said, were just in early drive units. “Today, we hold the same standard on both units that are being built,” he said. Elon got specific by stating that, “there was this one period of time we had … just before we transitioned into automatic grease injection into the spline of large drive unit, we had variation in how much grease was put into the spline, and if not enough grease was put into the spline, it would have premature wear…. But other than that, the large drive unit has been great. ” That getting technical enough for you?"
http://cleantechnica.com/2015/11/05...ciency-3-tidbits-from-teslas-financials-call/