I’m in the final stages of rebuilding the transmission on my
98 VDP. So far all has gone well & I now have it all
reassembled and am just waiting on a new Torque converter to
complete the job.
However, I have one question I’m puzzling over. I’ve read in a
number of places that the output shaft should only rotate in
one direction (in my case this is clockwise viewing the
transmission from the rear, which I believe to be correct).
However, I can also rotate the output shaft counterclockwise,
although with more force being required. As the shaft must
rotate in both directions for the car to reverse, I’m puzzled
as to whether my situation is as things should be, or if the
output shaft should only rotate in the counterclockwise
direction if reverse gear is engaged.
On the bench, all parts matched the manual requirements, so
I’m at a loss. Appreciate any input on whether what I’m seeing
is OK, or if this means I need to disassemble and reverify
that all is OK.–
SAR 98VDP
Vancouver Island, Canada
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from sarvdp sent Fri 24 Aug 2012:
Sar,
The output shaft should rotate both directions fairly freely as
clutches are not engaged. The added friction you feel are from the
one way rollers so all should be okay.
Did you have the A-Drum failure?
Darrell–
The original message included these comments:
However, I can also rotate the output shaft counterclockwise,
although with more force being required. As the shaft must
rotate in both directions for the car to reverse, I’m puzzled
as to whether my situation is as things should be, or if the
output shaft should only rotate in the counterclockwise
direction if reverse gear is engaged.
In reply to a message from sarvdp sent Fri 24 Aug 2012:
Thx Darrell
I did have the A drum failure. Lost about 3’’ of the lip which
allowed the pressure to leak out, but found the circlip still
in place. I found about 95% of the broken bits in the rebuild.
2’’ in the bottom of the B drum, 1/2’’ in the F drum and 1/4’’ in
the pan (plus a huge amount of shavings in the pan and
embedded in the frictions of the A drum. Most of the residual
oil in the tranny body & oil pump was loaded with fine
shavings as well. Based on my findings I highly doubt,
contrary to what some have recommended, that a rebuild that
doesn’t fully strip the unit down would have a long life
expectancy.
No other damage found (or measurable wear to the frictions or
any other parts after 145K miles) and all bearings were OK.
I did a breakdown and reassembly of the Valve body as well,
but found no issues. The bore for the main pressure regulator
was good and there was only a single 1/32’’ shaving in the
filter screen. All the solenoid screens were perfect and the
residual oil in the VB after the main screen was clean & all
orifices were clear. I haven’t replaced the pressure regulator
to the updated version as I can see nothing wrong with the
original. I did order a replacement on spec when I ordered the
rebuild kit and new A drum, but it was missed off the order &
I decided that as the VB looks good, to stick with the
original. Hopefully, not a decision I’ll regret some day.
My last assembly issue is now clutch operation. Last PM, I
made up a test plate modelled on the ZF unit using plexiglass
as many bimmer folk have done. All clutches save A are
operating OK, but I can’t tell if the problem is that I can’t
get enough pressure on the A drum for it to operate or not. I
may have to strip it back to recheck if I can’t get it to
operate today - although I really don’t want to as all bench
tests were good and all clearances on reassembly have been to
spec. Unless I’ve somehow got a blocked oil passage (which
shouldn’t be the case as all clearances are to spec) or I’ve
damaged/dislodged a sealing ring on reassembly I can’t see why
the test isn’t working.
My main hope is that the new Torque converter will clear a
mild driveline vibration at 50+ mph I’ve had for years that
has driven me crazy (lots of posts on my attempts to fix it).
The vibration started shortly after my original water pump
failed & things got v hot, so I’m working on the thought that
the lock up clutch was damaged by the heat. Fingers crossed.
Assuming the rebuild works OK on re-assembly, I plan on
putting together a post on lessons learned - as there is a
huge amount of info on the rebuild on the web, esp. from BMW
folks, there haven’t been many aspects of the job I’ve been
working in the blind on, just a few things in retrospect that
would make the job a little easier.–
SAR 98VDP
Vancouver Island, Canada
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In reply to a message from sarvdp sent Sat 25 Aug 2012:
Hello Sav…it has been interesting reading your trials and
tribulations and hopefully you are some where near the end of a
long and complicated road ;o))
Re. the vibration…I don’t know how the X308 TC is mounted as my
gearbox and TC was replaced befor I bought the car but on older
automatics the TC is usually checked for run out with a dial
indicator.
I will look forward to your summary of your experiences as this
sort of thing is invaluable for later access. ;o)
Looking forward to a positive outcome as you reinstate the box.
Cheers,
Maximus–
The original message included these comments:
Thx Darrell
I did have the A drum failure. Lost about 3’’ of the lip which
allowed the pressure to leak out, but found the circlip still
in place. I found about 95% of the broken bits in the rebuild.
2’’ in the bottom of the B drum, 1/2’’ in the F drum and 1/4’’ in
the pan (plus a huge amount of shavings in the pan and
embedded in the frictions of the A drum. Most of the residual
oil in the tranny body & oil pump was loaded with fine
shavings as well. Based on my findings I highly doubt,
contrary to what some have recommended, that a rebuild that
doesn’t fully strip the unit down would have a long life
In reply to a message from Exjay8 sent Sun 26 Aug 2012:
Latest update
I decided to pull the tower with A & B clutches yesterday to
see if I could find a problem. Both tested OK with air
directly applied to the oil passage bore (ie held pressure),
so I re-assembled and still found the same issue with my test
via the pressure plate orifice. Even with the plate lubed with
petroleum jelly (vaseline), I couldn’t get a full seal - but
could tell the Plexiglas was flexing and allowing air to pass.
Based on that I’m declaring tentative victory and will finish
reassembly pending arrival of the new torque converter.
As an FYI, I found many clutches are easier to test directly
using the plugs on the transmission housing with the channels
on the transmission housing fully blocked, rather than via the
pressure plate as it was easier to get a good seal for the
pressure gun nipple. Only problem with this method is that not
all clutches have the plugs tapped, this seems to have been a
change from the earliest version of the 5HP24.
On the TC question. What I’ve found in reading is that the TC
lock up engages via controlled slip with full lock up not
occurring until @ 57mph. My hope is that if there is damage to
the TC caused from the overheat experience, it may be causing
the lock up clutches to engage improperly leading to the
vibration. As the vibration normally smooths out at higher
speeds (70mph+), when full lock up should have occurred, the
possibility seems plausible at least - and for sure heat is a
major killer of TC’s. The baffling thing is that the vibration
has never gotten worse since soon after it started (in 2002)
but lots of other parts have been changed out since then…–
SAR 98VDP
Vancouver Island, Canada
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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In reply to a message from sarvdp sent Sun 26 Aug 2012:
SAR…Your explanation seems more than plausable.
The TC’s on these boxes are a very sophisticated unit and built to
exacting standards which means, yes, if the engine has suffered a
serious over heat, then that heat will be quickly transferred to
the TC and could cause irreperable warpage of the internal vanes
which could quite easily cause said vibration.
A new TC will obviate this if that is the case.
we wait in anticipation ;o))
Cheers,
Maximus–
The original message included these comments:
the TC caused from the overheat experience, it may be causing
the lock up clutches to engage improperly leading to the
vibration. As the vibration normally smooths out at higher
speeds (70mph+), when full lock up should have occurred, the
possibility seems plausible at least - and for sure heat is a
major killer of TC’s. The baffling thing is that the vibration
has never gotten worse since soon after it started (in 2002)
but lots of other parts have been changed out since then…
SAR 98VDP
Vancouver Island, Canada