bore wear Archives - Transmission Digest
CVT 7 Troubles

The CVT 7 used in Mitsubishi and Nissan vehicles (Figure 1) is unique in that between the pulley assembly and the differential is a planetary gear set controlled by a reverse brake, a low brake and a high clutch.

722.6/NAG 1

With the large number of 722.6 transmissions being used in both Mercedes vehicles and in Dodge and Jeep vehicles, where it is called the NAG 1, it is virtually certain that this transmission will end up in your shop for repairs. It may be that your shop refuses to work on Mercedes but Dodge and Jeep vehicles are all too welcome. And so it is in this way that if you have not worked on this transmission yet, you will. And it is not a bad unit to work on.

A Different Fix for an Old Problem

The problem of bore wear on torque-converter-clutch pistons has been around since lockup torque converters were born. The rotational restriction on the pistons is handled by splines, pins or fingers. But centering the pistons is generally the sole responsibility of the bore. Any out-of-balance movement of the piston will cause the piston bore to scuff against the turbine hub when it moves to apply or release the clutch. Indexing the piston to the turbine and balancing this unit helps minimize bore wear. (See the article on indexing TCC-piston damper assemblies to turbines, Transmission Digest, March 2006.)