I've created this web page because there is so much misinformation on the web and on forums.
BMW did not make the Automatic Transmission on the E46. They bought them from either GM (yes, General Motors) or from ZF.
The following information if for the E46's made for the US market. It may be correct for other markets, but, I have no way to verify this.
At the start of production BMW used the A5S360R transmission made by GM (5L40-E) for both the 323 and the 328. In March of 2000 they changed the transmission on the 323 to the A5S325Z Steptronic transmission made by ZF (5HP-19) and that stayed until the end of production. This is the one famous for the no reverse issue. See noreverse.org. The 328 continued to use the A5S360R GM transmission until the end of production.
With the 325i they started were the 323 left off, with the A5S325Z Steptronic transmission made by ZF. The 325i with the M56 engine continued to use that transmission until the end of production in 2005. The 325i with the M54 engine used it through Feb 2002 when they switched back to a GM transmission, but, this time the A5S390R, which I guess is a later generation 5L40-E with some improvements. That ran until the end of production in 2005. The 325Ci is a bit different story. It used the A5S325Z, GM transmission until Feb of 2003 when they switched to the A5S390R, ZF transmission (note: a year later than the 325i/M54). The 325xi and 330xi started off from the beginning with the A5S390R, GM transmission from the beginning and that lasted until the end of production in 2005. The 325ti is a bit of an oddball. It started off with the A5S390R, GM transmission in 2001 through the end of Feb 2003 when it switched to the A5S325Z and that lasted until the end of production in 2005. (The M56 engine is a special SULEV engine only sold in California, New York and Massachusetts starting in model year 2003 and in Vermont starting in model year 2004)
The 330i/ci started off with the A5S325Z, ZF transmission until the end of Feb 2003 when they changed to the A5S390R, GM transmission. The 330xi used the A5S390R, GM transmission from the beginning and that lasted until the end of production in 2005.
ATF fluid. These transmissions are lifetime fill. They expect the fluid to last as long as the rest of the car, but, this goes against everything we grew up with so if you want to change the fluid in your automatic transmission check the label on the bottom of the oil pan on the transmission for the correct fluid part number. If that label is no longer there or unreadable you can use the following table as a guide. Remember fluid level can only be checked within a very narrow range of temperature, approximately 100 F (85 - 120F)
A5S360R (GM 5L40-E)- Texaco ETL 7045 E
A5S390R (GM 5L40-E) - Texaco ETL 8072 B
A5S325Z (ZF 5HP-19) - Esso LT 71141
Tightening torque
A5S360R & A5S390R - 20 Nm (15 ft-lb) for both the fill and drain plugs.
A5S325Z - 35 Nm (26 ft-lb) for the drain plus and 30 Nm (22 ft-lb) for the fill
plug.
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