A friend has asked if I can help find him answers to a problem with his, otherwise very nice, E32 730i.

The car will drive in reverse, or 3rd gear (? recovery mode) only.

A dealer and 2 specialists have said it checks out OK on their diagnostics, but is probably an electrical fault which could cost £bundles and £bundles to trace.

Anyone experienced this? Any pointers or ideas...or even guesses?

Cheers guys and gals

Are the other gear selections appearing in the digital dash display?  i.e. when selecting Drive or 1st or 2nd gear, does the display show D, 1 or 2?  It may be something as simple as poor electrical connections which might be cured by giving the gear selector switch a good clean out.

What about the fluid level in the autobox.  Is it clean?  Does it smell burnt?

I don't know much about gearboxes but I do know that the oil in them needs to be kept clean and topped up...

Sussex Paul wrote: Sorry, should have said. Yes, the selections are showing on the display. I think you're possibly right about connections, but where to start?

If its showing on the display, it must be recognising what gear its in so doubtfull its an elec fault, first thing i would do is get the oil/filter changed.

E34 M30 535i SPORT



                                

Hi,

Did the "Trans Program" display on the dash?  Is the shift selector getting hot?  (ATF fluid overheating)

Sounds like your transmission has gone into failsafe mode, which can happen if...ATF gets too low, is the wrong grade, clogged transmission filter, amongst other things.  But from your last post it sounded like they replaced the ATF (you said oil)

Often the fault codes from the ECU or TCU (engine, transmission control units) will indincate something like a  bad speed sensor, DME control relay, intake problem etc...all of which are relatively inexspensive to replace. Did they dealer say both retuned no fault codes?

Ian

Ian,

"Trans Program" displays with ignition on. Shift selector not getting hot, and ATF correct.

Both diagnostics reported no faults, which we have to presume means no fault codes. However, both maintain the problem is electrical but not control units.

It does sound like failsafe mode - how can we get out of it?

Ian

This is Jerry - the owner of the said 730i with only third gear - I'm sure it is in the 'failsafe' mode - but would love to know how to track down what's causing it to be in that mode.  As said before the diagnostic by BMW Chandlers (Hailsham),  Sussex Autos and also LMW - a semi-BMW dealer showed no faults - so they were suggesting getting wiring diagrams out and trying to track it down by process of elimination.  That could be time consuming out expensive!  Any clues how to speed up the process?

Thanks,  Jerry

Jerry,

Suggest you try a post here...

http://www.the7seriesregister.co.uk/forums/ - http://www.the7seriesregister.co.uk/forums/

There's quite a few E32 experts there who know a lot more about the slushboxes than I do.

Jerry ALBONE wrote: Ian This is Jerry - the owner of the said 730i with only third gear - I'm sure it is in the 'failsafe' mode - but would love to know how to track down what's causing it to be in that mode.  As said before the diagnostic by BMW Chandlers (Hailsham),  Sussex aAutos and also LMW - a semi-BMW dealer showed no faults - so they were suggesting getting wiring diagrams out and trying to track it down by process of elimination.  That could be time consuming out expensive!  Any clues how to speed up the process? Thanks,  Jerry

Hi Jerry, If the BMW dealer hooked your 730 up to their DIS computer and it returned no fault codes I would hazard a guess that the auto box has a clogged valve or jammed solenoid inside it...but as per last post worth investigating more with other E32 owners.

You may find that BMW dealers are also somewhat reluctant to work on auto trannies and will take the easier option and quote you an entire replacement! 

Regards

Ian

Jerry http://bmwe32.student.utwente.nl/johan/gearbox_swap/gearbox_swap.html - here is a great article with some pics of open heart surgery on the tranny ...you can see the valves, solenoids and everything...not for the squeamish!

Ian

aussie840 wrote:   Jerry http://bmwe32.student.utwente.nl/johan/gearbox_swap/gearbox_swap.html - here is a great article with some pics of open heart surgery on the tranny ...you can see the valves, solenoids and everything...not for the squeamish! Ian

Great link!

Interesting fault with your 7.  Em not sure on this one.  I would have thought that if you only have a couple of gears, this would be picked up by the diagnostics. 

Try a different tranny specialist. 

BMW will not be able to help as all they can do is swap in/out auto gearboxes and check and fill the fluid level.  They are about as much use a chocolate teapot when it comes to fixing autoboxes.

Sorry I can't be of much help.

Andrew

Hi Guys

I found a guy down in Poole Dorset UK (Autotek) who is a specialist in ECU's - he has diagnosed that the ECU controlling the Autobox is beyond repair and needs replacing.  Being a specialist I left it in his capable hand to find a replacement (reconditioned / 2nd hand I presume) - he guessed it would be about £80 - 90.  3 weeks on he has no joy - does anyone out there know where I could get the said offender?!

Thanks

Jerry

Should the worst happen and you need a 'box, would this be any good to you:

http://forum.bmw5.co.uk/index.php?showtopic=6605 - http://forum.bmw5.co.uk/index.php?showtopic=6605

Probably the same 'box, but be quick!!!

BTW, this 'box isn't mine, it belongs to a member of another forum I subscribe to.

Hi Guys

I've given up trying to fix the electric signal problem with my E32 730i G reg Se Auto - Engines great, gearbox completely overhauled (Sept 2004 still have receipt), 135,000 miles, MOT 'til March, still driveable in 'Fail-safe' mose (3rd and reverse).

Great for spares or repairs - any offers guys?

Jerry (07886 861458)