As of 2016, Volkswagen transmission codes for 020 four- and five-speed gearboxes include GN for four-speed vehicles to model year 1980, and GC and GN for four-speeds from 1981. Code ACH covers VW's 1985 model 1.6-liter diesel-powered vehicles, and 4S, AOP and AGS are the codes for 1986 through 1990 1.6-liter diesels. CLK covers 01M four-speed automatic transmissions in the 2.0L Golf/Jetta III and the Passat from 1995. Volkswagen uses dozens of transmission codes for its vehicles.
Transmission codes identify the correct transmissions for vehicles. Mechanics use the codes to ensure they select the proper transmissions when customers order rebuilt transmissions. For 02M six-speed, hydro clutch, dual final drive Volkswagens, the automaker uses transmission codes KDQ, JLW and KNU for its 2008 through 2009 Golf/R32/GTI 2.0-liter engine vehicles. GVT and JLW are the codes for 2006 through 2007 Golf/R32/GTI 2.0-liter models. FML 2nd edition, ERR, FZQ and JNB are the codes for the 2002 through 2005 VW Beetle.
Volkswagen transmission codes for 020 gearboxes are on the bottom of the transmissions. The date of manufacture is the set of numbers after the transmission code. The date format is D-D-M-M-Y. For Syncro all-wheel drive 020 gearboxes, the transmission codes are 4Z, ARM and ATZ. AXR is the code for the Syncro Country all-wheel drive model.