An automatic transmission is just that- automatic, consequently
most people tend to pay very little attention to it until a
major problem rears its ugly head.
Picture the scenario- you are driving along in the lap of
luxury, the satellite radio blaring and the heated seats on.
You've become accustomed to the comfort level and great driving
experience brought to you by BMW.
You decide to stop at the local convenience store on your way
home to grab some ice cream for the kids and a bottle of water
for yourself. Upon returning to your car, you start it up, check
your rear view mirror, put the shifter in reverse and then the
unthinkable happens- the engine just revs as if it is in neutral
and the car goes nowhere!
To eliminate confusion, this doesn't apply to vehicles equipped
with the GM 5L40 E transmission, just the ones with the
sometimes problematic ZF5HP19. The 5L40 E has some issues of
it's own that are beyond the scope of this article but are
certainly going to be the subject of another.
The failure rate for these transmissions seems to be very high
and is expected to become much more of a problem as time goes
Typically, the vehicle is working perfectly while driving
forward but when it is put in reverse there is a complete and
permanent loss of movement to back up.
Reverse is typically a major feat for any transmission to
accomplish- imagine the demands that are placed on a gearbox as
it is asked to reverse the torque of your engine so that you can
back up your nearly 4000 pound vehicle.
By far, the most common cause of the reverse problem in BMW's
is the failure of the "D-G" clutch drum. Specifically, the snap
ring that retains the D or reverse clutch breaks out of the
clutch drum resulting in an inability for the clutch pack to
The good news is that there is hope in regards to a proper
repair. The factory has released an updated part that so far
appears to be a permanent fix for this problem.
In our testing and in conjunction with several hundred
successful repairs at our facilities, the new part seems to be
metallurgically superior in several ways.
We have found that there is an improved radius area as well as
slightly thicker casting. In addition to this, the grove that
retains the snap ring is also relocated further away from the
edge of the drum.
With this issue addressed and attention to detail in several
other areas of the ZF5HP19 unit, the transmission can be
repaired to "better than new" condition by a competent
transmission rebuilder / remanufacturer. In fact, when properly
repaired, the ZF gearbox becomes quite robust and can provide an
almost indefinite service life.
About The Author: Joe Sirugo o is co-owner of Trans Specialties
and has been in the transmission repair industry for over 20
years. Visit his website- http://www.autotransparts.com for more
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BMW No Reverse Transmission Problem
Author: Joe Sirugo
This article deals with the reasons behind an unexpected loss
of reverse in certain BMW automatic transmission equipped
vehicles, specifically the 3 series and 5 series vehicles that
use the ZF5HP19 or "steptronic" transmission. This includes the
popular 323i, 323ci, 325i, 328i, 330i, 525i, 528i, 530i, X3 and
X5 models well as some others built in the 1999 to present model
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