01J Archives - Transmission Digest
CVTs – Do I Rebuild Them or not?

The question of whether to rebuild a continuously variable transmission (CVT) has increased dramatically this past year on our technical hotline, and I thought I might risk making a few comments about this subject.

The call comes to our technical hotline a few different ways. The question has been: “Why are people saying you cannot rebuild CVTs?” or, “Is it worth trying to rebuild one of these” or, “What am I getting myself into if I try to rebuild one? What tools do I need?”

My answers to these questions follow.

01J CVT: Diagnosing and Repairing Code 17090

A 2003 Audi A4 with an 01J continuously variable transmission (CVT) came to our shop. The customer complained that the vehicle was sluggish in forward and had no reverse and that this would take place only when all the lights in the gear indicator “lighted up and flashed.”

The Bucking Audi

The continuously variable transmission (CVT) used in Audi’s A4 and A6 vehicles, called the 01J or Multitronic, could show up in your shop with a bucking complaint. This style of CVT (see Figure 1) does not use a fluid coupling as a pass-through device for engine torque input. This means that when the vehicle is engaged or comes to a stop in gear, the forward or reverse clutch must slip. When the brake is released and the throttle is depressed, the clutch applies and the drive and driven pulleys begin to move in relation to each other to provide gear ratios.

It’s an Inside Job

The 2003-and-up Audi A4 and the 2002-and-up A6 with a 1.8- or 3.0-liter engine use a continuously variable automatic transmission known as the Multitronic® 01J (see Figure 1) and also referred to as the VL300. The core of this article is not that this transmission is a CVT. The focus is on what’s inside the transmission other than the drive- and driven-pulley set.