Irritating Bug In The Auto Gearbox

December 4, 2009

Hi

Don't know if there are anyone here that has an E12 with automatic gearbox (not MMT), but I have lately noticed a slight change in behaviour from the gearbox. Sometimes it won't engage the overdrive.

Normally when I drive down a long hill, I brake lightly, and the overdrive disengages, so that the revs increase and the speed is maintained and will not exceed noticeably. When I then touch lightly on the accelerator, the overdrive engage, revs decrease and car will start rolling so that the speed increase with gravity. This will now not happen! I kan press the accelerator as much as I'd like, and it's still in overdrive! To engage overdrive, I have to press O/D button twice.

Another thing that I noticed today on my way to work was that the overdrive suddenly kicked in without any actions from me. I was just rolling down a slope, and did't touch the brakes at all. This has never happened before. I tried excessively to activate overdrive again without pressing the O/D button, but it just wouldn't.

Has anyone experienced anything like this? Could it be any sensors that might be faulty?

December 4, 2009

I have an e12 with a proper auto box ( not MMT)

Are you referring to dropping a gear by pressing the button on the handle of the auto selector, that shows a yellow light on the speedo. If not I have never know mine to change down a gear by itself when going down a hill. I sometimes wish it would.

Perhaps yours is different from mine

December 5, 2009

I have an e12 with a proper auto box ( not MMT)
Are you referring to dropping a gear by pressing the button on the handle of the auto selector, that shows a yellow light on the speedo. If not I have never know mine to change down a gear by itself when going down a hill. I sometimes wish it would.
Perhaps yours is different from mine

Yeah, I have the proper gearbox. It will disengage the overdrive (without having to press the button) if you press lightly on the brakes for a couple of seconds. Then it will keep the overdrive disengaged until you press the accelerator again. This feature is not working properly any more.

December 5, 2009

I wish mine would do that. I have to use the button on the handle of the selector.

Hope you manage to get it fixed, does sound like a sensor.

Best wishes

December 14, 2009

Seems like it was the newly installed LED tail lights that made the gearbox act strangely. When I replaced the LEDs with the old bulbs, everything went OK again... So now you're warned!