Trans Program problem in pull away

[petebanham]

Hi,

I know there has been a lot written about this problem already, and I have read the good write up at www.bmwe34.net but none of these seem to match my symptoms, so I was wondering if anyone has any more ideas.

I have a 1990 525I SE E34 Auto with the M50 engine which I have just bought. The problem is if the shift selector is in D and I pull away with any more than1/4 throttle the Gearbox goes into limp mode (stuck in third gear) and the “trans program” light comes up on the dash, this can be reset by turning off the ignition waiting a minute and then restarting and the gearbox is back to normal. If I drive it manually using the selector then all seems well and it does not fail, so this leads me to believe that the mechanics of the box are fine. Once the car is moving shifting into D is fine and everything works well, kick down etc, but if I come to a stop and pull away again without manually selecting a lower gear, then third gear and the dash bong strike again!

The other gearbox related symptoms are that the parking brake doesn’t hold the car properly (not sure if this is related) and also the selector light on the dash sometimes seems unable to decide what position the selector is in, in D for example it may show D or blank and in 4 if can flick between displaying 4 and D (it seems much more stable in position 2 and 3.

I would be grateful if anyone has seen this before or has any ideas and also was wondering if there was any adjustment on the selector lever, as given the dash lights not being consistent it occurs to me that the computer may be having a problem identifying what position the selector is in, although I am not sure why this would only have an effect on pull away and not once the car is moving.

Many thanks in advance for any help and suggestions

Pete

[Kalevera]

Pete,

Welcome!

Search "neutral position switch" on the forum. Pull the switch/inspect/clean/replace it if it's burnt or otherwise beyond repair.

I'll wager that the shift gate has wear on the detents, which confuses the switch, and in turn the trans computer. Fix the visible electrical problem first (assuming the fluid level is correct and the fluid is in good health), and let's see what happens.


best, whit

[petebanham]

Lowell,

Many thanks for the quick responce, lots of usefull stuff on the of the selector lever, switch etc. The fluid seems fine but I have not changed it as yet.

The selector switch/linkage was going to be my first port of call so I will strip down at the weekend and see how it goes.

Cheers Pete

[NovceGuru]

You know...my car does the same thing- where the selector in the dash is sometimes blank and if you fiddle with the selector you can make it go blank/D. I've never really payed much attention to it since I haven't had any problems with my granny tranny (200k miles, to much junk mail this morning) so far, knock on wood. Is this something I should be worried about? A while back I took my gear selector/console area apart because I was going to redo the veneer and noticed lots of wear on the little "teeth" the selector seems to rest against. Thanks.


NovceGuru

[petebanham]

A brief update,

I striped down the selector switch and cleaned it tonight and it got a bit better, but still not perfect, although the lever gate looked OK. It seemed that the position that the selector rested in when in a given position did not line up with where the switch wanted to be, e.g. when the lever was firmly in D the switch was bordering on N. I couldn’t find any adjustment in the cable or switch, does anyone know if there is any adjustment at the other end of the selector cable, where it goes into the box?

Anyway given that it was dark and cold, so crawling around under the car was not very appealing, I decided to modify the selector switch mountings, by elongating the mounting screw holes and removing the locating pin on the bottom of the switch (it broke off easily) I was able to move the selector switch forward by about 4mm and refit it.

I have only taken the car for a quick drive but, touch wood, it did not go into “get you home” mode and the indicator on the dash was much more stable. I am not using it tomorrow but have a long drive to do on Friday so it will get a proper test then and I will post the outcome.

Thanks again for the advice

Pete

[dacoyote]

Let us know please

[petebanham]

Drove 150 miles today, mixture of town and motorway driving, with the box in “D” the whole time and had no problems so it looks like modifying the selector switch did the trick with the trans program problem. It didn’t however have any effect on the parking brake, bit of a long shot that one really :)

If anyone knows of any commom causes that allow the car to roll with the gear selector in “P” I would be grateful for the suggestions, especially ones that don’t involve getting the box stripped down!

Cheers

Pete

[petebanham]

The final chapter of the story, hopefully. Having got hold of a Bentley manual it said that an incorrectly adjusted selector cable could cause the car to roll when in “P” and that the adjuster is under the car, at the box end.

So up the car when and I made sure that the lever on the gearbox was as far forward as it could be when the selector was in park, I only got a 1 or 2 mm adjustment but it seem to make all the difference and the parking “brake” starting working, great but………

….. The dash gear indicator went dodgy again, so I ended putting it back to how it was fitted originally!

So the moral of the story is that 1-2 mm adjustment on the sector cable can cause the trans program problem and stop the parking brake working.

As a side note, while I was under the car I noticed that the transition mountings where clearly not the original ones so I noted the box code and it turns out the car has been fitted with a 5HP18 transition, that apparently should be fitted to 92-95 530 and not a 1990 525i, but it seems to work and I have got an extra gear thrown in.

Pete