BMW Automatic Transmission – No Reverse – 6-cyl Models With A5S-325Z / ZF 5HP-19
This answer is applicable for many BMWs in addition to the one listed below.
car year: 2001
car model: 325i
Our vehicle will not move when put into reverse. I checked to see if the shifter was loose or wouldn’t move but all looks good. There is no problem with any other gears. I hope it isnt bad……..
In this case (I’m sorry to say) ….. it is bad.
Your 2001 325i is equipped with the ZF manufactured A5S-325Z transmission (also known as the ZF 5HP-19). This transmission was installed on various 6-cylinder 3, 5 and Z BMW models in the late ’90s and early 2000s (models with M54 engines only). Note that the similar 3.5.X and Z models from the late 90s through the mid 2000s also used the GM manufactured A5S-360R and A5S-390R transmissions. The specific model and date of production will determine which transmission is used in the vehicle. These GM transmissions also have a common no-reverse issue, but the causes are totally different. For info on no-reverse for the A5S-360R/390R transmissions see the link below.
The A5S-325Z automatic transmission that is used in your 2001 325i has shown a tendency to fail in the mode of “no reverse”. This is due to a failure of the D-clutch drum – clutch retainer snap-ring groove. Repair involves full disassembly and replacement of the D-clutch drum. Of course, since it is all apart and the vehicle likely has somewhere around 100,000 miles, it would be prudent to reassemble the transmission with all new clutches, seals, etc. in other words install a rebuild kit. Note that the replacement D-clutch drum that we offer is an improved unit and the snap-ring groove area is strengthened and reinforced.
We also suggest that a full master rebuild be performed while the transmission is disassembled. This would include all of the clutch and wear parts as well as the seals and gaskets. If the transmission has around 100,000 miles of use, it would only make sense to reassemble it with the new fresh parts and start with a basically new transmission, since the highest cost of a regular rebuild is the labor to remove and disassemble the transmission.