1991 535I Auto Trans Question

[handymn1]

I have a 91 535 I with 100,00 miles on it. My son was driving it when this happened. He said he was going about 40 mph on a hilly road when he started to go up a hill he had begun to give it some gas when it seemed to jump out of gear. No grinding noise, no clunk, just out of gear. It will not move at all , forward or reverse. We trailered it home. On the dash we have 2readouts. One says low coolant. The other says check owners manuel.
I have checked the coolant it is full. I also checked and bled the system, no air. the transmition fluid is not low or burnt. It is however a little discolered.
I would like to know what checks I can do here at home to diagnose the computer for the motor and the transmission. I do have generic OBD code reader. and have printed some of the codes I got online. As of right now I have not checked these codes. I have just been to busy.
I would also like to know if any of these code and or sensors would take the transmission out of gear as some sort of failsafe. I have been reading some on this and I see where it has a limp mode that puts into 3rd gear and it should have reverse. I have nothing, no forward or reverse and it makes no noise at all.
Help. I am new to beemer repair. I have however spent many years working on everything that is American made. My experiance is , in the 70s I worked as a mechanic for Chevrolet. In the 80s I was sevice manager for a very large independant shop hear in Houston from 1990 I have just worked rebuilding old cars and doing bodywork here at home. I have not done a lot of computer work.
Thanks
Chuck

[shogun]

o.k., fine:
first of all you need the tech information, download the 61.14MB here, second from left on top
http://luuk.xs4all.nl/bmwboeken/
Then go to my website below, scroll down, there is a link to european transmissions website, read all that.

wiring diagrams by year
http://shark.armchair.mb.ca/~dave/BMW/e34/

Do you have the gear and mode indicated in the dash cluster?
Must be, otherwise clean the switch under the handle.
But to that later or visit the website of Gale, link on my website too.

[shogun]

one more simple check, gear shift lever cable, check if broken
http://www.realoem.com/bmw/showparts.do?model=HD23&mospid=47408&btnr=25_0049&hg=25&fg=15

[handymn1]

I am checking these things now. I will get back later .
Thanks
Chuck

[Robert K]

First, I'd doubt that the low coolant has anything to do with it. That is most likely a totally separate issue.

The first thing I would check is the fluid level, which you said is fine. Since the inner workings of the tranny depend on the putting the fluid under pressure, if you have no fluid, you have no pressure. Things quit working when there's no fluid in the trans. One thing that could happen even if the fluid level is correct is that the filter is completely stopped up. It's very simple to remove the pan and replace the filter. Believe it or not, you can pick up a filter at most normal chain automotive stores. That is something I would definitely check into since it's a cheap fix and something you can do yourself.

If the fluid and filter is not your problem, then it sounds a bit more catastrophic to me. Typically, if the sensors or computer get a flaky signal, the tranny goes into "limp home mode", which essentially gives you third and reverse. If you have absolutely no gears at all, then you are not in limp home mode.

I've never really torn into an auto trans nor do I really understand the inner workings much at all. So, I really can't tell you what possible things have gone wrong. You could do a Google search for either the problem or for BMW forums or BMW sites in general. Hopefully you'll have a few more replies on this forum from some more knowledgeable people than myself.

Good luck!

Robert K
1991 535i