What a Drag
The ATSG tech line frequently receives calls related to engine stall or even a partial-stalling condition that could be easily mistaken for an engine-performance problem in 1995 and later Audi/VW vehicles with the 01M transmission.
Shift By Wire
This article presents a situation that ATSG technical adviser Gerald Campbell handled regarding a ZF 6HP26 in a BMW with Reno Partipilo, Sal Scardina and Joe Russo from Continental Transmission in Bridgeview, Ill. But before we can cover it, we first need to present a bit of information that will help to make sense of the problem and what it was that corrected it.
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.
