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4951Re: [bmw e28] Re: ATF pump

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  • Steve
    Jan 20, 2007
      Just a quick note from the uk.
      I've done a lot of research on this ... its only a problem with poorly maintained
      transmissions where various bushes,etc get very slightly worn and
      allow a little bit too much oil to seep past, leading to an unwanted pressure buildup
      behind the front clutch pack.
      (Later 4hp22 boxes had a small drain hole drilled in a certain place to overcome this problem).

      The main thing to watch for ... after driving a while to ensure the gearbox has warmed up,
      put it in neutral and with no brakes, just see if there is any tendancy to creep.
      My 525e (uk) did it for a couple of years ... every time i went into neutral it had this slight
      urge to move forward ... applying a few revs would actually stop the forward motion (obviously
      reducing to drag between clutch plates by increasing the rpm difference between them).

      Anyway, my box did fail, i fitted a replacement which, to this day has not shown any tendancy
      to drag its front clutch pack whilst in neutral. (6 years of use to far!!)
      In fact, with a hot gearbox ... i can stop and without switching the engine off i can jack up
      one of the rear wheels, put it in neutral with the handbrake off and still see no apparant drive
      through to the rear wheels.

      This i assume is an ideal situation ... there is no drag at idle rpm = healthy gearbox which can take
      the odd standing rev in neutral without self-destructing.

      Regardless, if i get stuck in traffic i pull the handbrake on and leave it in drive!!

      Steve
      Uk


      Bmw 525e uk spec 11.0:1 compression, fitted with 323i 731 head and valve gear, viper 2
      performance chip to suit these high revving stroker engines and a 4.1:1 differential in
      place of the stock 3.06:1 unit.

      22 years old and faster to 60mph than the new 330d !!!






      ----- Original Message -----
      From: pld1952
      To: bmwe28@...
      Sent: Saturday, January 20, 2007 3:33 PM
      Subject: [bmw e28] Re: ATF pump


      Turns out that running the engine in Park has the same effect as
      running it
      in Neutral. The front clutch pack has no mechanism for
      depressurizing when
      a drive gear is not selected, so revving the engine, or even running
      it,
      will still power the transmission's internal fluid pump, increasing
      the
      pressure within the clutch pack until failure.

      BMW put out a service bulletin on this, recommending that ZF
      transmission
      cars which needed to be idled for whatever reason be shut completely
      off
      for thirty seconds, then restarted in Park or Neutral without EVER
      going
      into a drive gear. So you're all right idleing as long as you don't
      ever put it into drive or reverse.

      I don't know that anyone ever told me which years of cars had the ZF
      transmission and which had the GM unit. I'm sure your service advisor
      would be happy to give you that information.

      Hope this was of help. One of my friends has a 750 that he regularly
      puts
      into neutral at stoplights. He was very surprised when I told him
      about
      this problem. He said that the previous owner had mentioned having
      the
      trnasmission replaced at 70,000 miles because it blew while revving
      in
      neutral. He didn't realize that type of failure was a congenital
      defect,
      not an isolated incident.

      Go here for how it all works
      http://www.bmwmotorsports.org/BMW_docs/transfund1.pdf

      The next step is to check pressure with a autotrans pressure guages

      Phil

      --- In bmwe28@..., Brett Peavey <pv9@...> wrote:
      >
      > correct...and they are.
      > --- pld1952 <pld1952@...> wrote:
      >
      > > Lets start over, With the engine running and warmed
      > > up in park the
      > > fluid level needs to be between the min and max
      > > marks.
      > >
      > > Phil
      > >
      > >
      > >
      > >
      > >
      > > --- In bmwe28@..., Brett Peavey
      > > <pv9@> wrote:
      > > >
      > > > I recently bought the car. and I drained nearly 6
      > > > quarts of tranny fluid out. so there was too much
      > > in
      > > > the tranny so i thought that the pump may be
      > > gunked
      > > > down.
      > > > --- pld1952 <pld1952@> wrote:
      > > >
      > > > > Not questioning your abilities but are you sure
      > > the
      > > > > fluid level is
      > > > > correct? Sure sounds like low fluid.
      > > > >
      > > > > Phil
      > > > >
      > > > >
      > > > >
      > > > >
      > > > >
      > > > >
      > > > > --- In bmwe28@..., Brett Peavey
      > > > > <pv9@> wrote:
      > > > > >
      > > > > > symptoms----when cold; the tranny will engage
      > > the
      > > > > 1st
      > > > > > and reverse barely...and every few seconds it
      > > will
      > > > > > jolt into gear and then slip back out allowing
      > > for
      > > > > 2
      > > > > > maybe 3 feet of movement.
      > > > > > when warm the tranny wont engage but every
      > > minute
      > > > > or
      > > > > > so, giving me the same result of 2-3 feet of
      > > > > movement.
      > > > > > --- Steve Haygood <sfhaygood@> wrote:
      > > > > >
      > > > > > > what are the symptoms ? There is a rebuild
      > > kit
      > > > > > > available for the trans that
      > > > > > > includes all that you would need
      > > > > > > Steve
      > > > > > >
      > > > > > > Steve Haygood
      > > > > > > BMW CCA 6 Series Register Director
      > > > > > > 03/04/05 Official 5er Fest Sponsor
      > > > > > > 03/04/05 Official Sharkfest Sponsor
      > > > > > > www.stevehaygood.com
      > > > > > >
      > > > > > >
      > > > > > > _____
      > > > > > >
      > > > > > > From: bmwe28@...
      > > > > > > [mailto:bmwe28@...] On Behalf
      > > > > > > Of Brett Peavey
      > > > > > > Sent: Thursday, January 18, 2007 4:43 PM
      > > > > > > To: bmwe28@...
      > > > > > > Subject: [bmw e28] ATF pump
      > > > > > >
      > > > > > >
      > > > > > >
      > > > > > >
      > > > > > > can the atf pump on my 87 535i be replaced?
      > > can
      > > > > it
      > > > > > > be
      > > > > > > cleaned and repaired? or do i need to
      > > replace
      > > > > the
      > > > > > > whole transmission?
      > > > > > >
      > > > > > > Brett Peavey
      > > > > > > Microwave Component Sources
      > > > > > > Ph. 904.721.3711
      > > > > > > Fax. 904-721-3714
      > > > > > > Cell. 904.210.6573
      > > > > > > PV9@ <mailto:PV9%40Yahoo.com>
      > > > > > > www.microwavecomponentsources.com
      > > > > > >
      > > > > > >
      > > > > >
      > > > >
      > > >
      > >
      > __________________________________________________________
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      > > > > > > [Non-text portions of this message have been
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      > > > > > >
      > > > > > >
      > > > > >
      > > > > >
      > > > > > Brett Peavey
      > > > > > Microwave Component Sources
      > > > > > Ph. 904.721.3711
      > > > > > Fax. 904-721-3714
      > > > > > Cell. 904.210.6573
      > > > > > PV9@
      > > > > > www.microwavecomponentsources.com
      > > > > >
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      > >
      >
      __________________________________________________________
      > > > > _______________
      > > > > > Don't pick lemons.
      > > > > > See all the new 2007 cars at Yahoo! Autos.
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      > > > > >
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      > > > >
      > > >
      > > >
      > > > Brett Peavey
      > > > Microwave Component Sources
      > > > Ph. 904.721.3711
      > > > Fax. 904-721-3714
      > > > Cell. 904.210.6573
      > > > PV9@
      > > > www.microwavecomponentsources.com
      > > >
      > > >
      > > >
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      >
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      >
      > Brett Peavey
      > Microwave Component Sources
      > Ph. 904.721.3711
      > Fax. 904-721-3714
      > Cell. 904.210.6573
      > PV9@...
      > www.microwavecomponentsources.com
      >
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      __________________________________________________________
      _______________
      > Don't pick lemons.
      > See all the new 2007 cars at Yahoo! Autos.
      > http://autos.yahoo.com/new_cars.html
      >






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