The Truth About Cars recently published an inside look at where the Ford and General Motors collaborative effort stands on the upcoming 10-speed automatic transmission. The transmission is being co-developed by both companies to be used in next generation rear-wheel drive trucks and cars.
Patent sketches give us an idea on how the engineers at Ford are developing their newest generation of transmissions, being the most cogs we’ve seen in a vehicle ever. Educated guesses combined with patent information help paint a picture of how the new 10-speed should perform, and how it will work. The unit is estimated to weigh no more than GM’s 8L90 8-speed do to clever packaging similar to the current 8-speed designs on the market. To share a few technical details, we’ll quote TTAC directly:
-There are a total of 10 forward ratios (of course) and 1 reverse ratio
There are six forward under drive ratios (i.e. the input turns faster than the output
There is a direct drive ratio where the input and the output shafts spin at the same speed
There are three overdrive ratios (i.e. the output turns spins faster that the input)
-There are 4 simple planetary gear sets, just like the ZF 8HP and the GM 8L transmission families
-There are six shift elements (as compared to 5 for the ZF 8HP and the GM 8L)
2 brakes (A and B) that are nested (one shift element is packaged inside the other)
4 clutches (B, C, D, and E), two of the clutches (D and F) are nested as well
-For any of the 10 gear ratios, 4 shift elements are closed and two are open. Consequently the frictional losses are likely to be no worse than the 8 speed transmission designs
-The nesting of shift elements means that the overall package size will be pretty similar to the 8 speed transmission designs
-All shifts up and down need one shift element to be opened, and another one to be closed simultaneously. This is identical to how the ZF 8HP and the GM 8L transmissions work. The shift performance should therefore be very good.
Some of you may recall a story of a 2015 Ford F-150 prototype leaving the General Motors Milford Proving Grounds earlier last year. This was more than likely to do with the development of the new 10-speed. Additionally, rumor has it the first prototypes of the 10-speed transmission were installed to vehicles last year, and controller development is ramping up as you read this. Late 2015 may be an estimate as to when we would see the new transmission, but 2016 is more likely. It will be interesting to see where CVTs end up in the competition, as the extra cogs found in this new 10-speed design are able to handle more torque than a CVT can in its current state. It’s also another necessary step to meet upcoming federal fuel economy standards as they near closer.