Volkswagen AG 0C8

Transmission general data

The 8-speed 0С8 (or TR-80SD according to Aisin) is a new generation of Aisin RWD transmissions. It was designed in 2006 for VAG (Volkswagen-Audi) as an alternative to DSG, which still can not function reliably with powerful engines.

This transmission was installed on Audi Q7 equipped with diesel engines V6-V8 from 3 liter capacity, and the torque capacity over 700 Nm. The same trasnmission design adapted for off-road Lexus cars has been used since 2007 under the name AA80E\F.

In the winter of 2010, this 8-speed transmission fully entered the foreign market, where it replaced its 6-speed predecessor TR-60SN on Porsche Cayenne (2010 - 2014) and on Tuareс (2010 - 2014) in different sub-versions for TDI diesel engines with the capacity from 3.0 up to 3.6 liters (Audi -TFSI). This transmission was used by American automakers for Cadillac CTS VSport in 2014 under the name TL-80SD. The competitive model for above mentioned gearbox is ZF 8HP70. This transmission was designed with usage of successful TR60-SN elements, but the valve body and the overall construction of transmission components and electrics were significantly modified. Most of the parts are not interchangeable with the predecessor. It is the most powerful of modern RWD Aisin transmission capable of transmitting the torque up to 800 Nm.

Technical issues and repair guidelines

This gearbox as all Aisin RWD transmissions is considered to be “invincible” and maintainable, designed to travel up to one million kilometers with minimum number of overhauls.

The repair kit of gaskets and seals is ordered for reassembly in order to restore leak resistance of jointing edges by replacement of rings and gaskets that helps to the valve body in regulation of gear shifting by the oil pressure. The whole kit of friction elements is replaced when some components get burned. At the same time, it is recommended to change the torque converter frictions in case of burned ATF.

For this transmission automakers used a new torque convertor with a multi-disc lockup clutch in order to guarantee a prolonged service life of torque converter frictions (over 200 thousand kilometers) and at the same time allow the driver to accelerate with the help of forced blocking of the torque converter lock-up clutch in "slippery mode". It significantly increases the transmission efficiency, improves acceleration characteristics, but wears out hard-working frictions of the lock-up. The valve body of this transmission differs from its predecessors TR-60 and TF-60. This valve body will get clogged if it is used with contaminated ATF for several years. Aisin solenoids in contrast to ZF solenoids can withstand much more open-close cycles.