Having auto tranny problems...control module related...

[MTechnik540i]

Hey guys...let me start of by saying merry christmas eve, hope everyone is enjoying thereselves. Now, to the problem...my mom goes to drive the 540ia this morning and later into her commute, while she's slowing down for a stoplight the OBC reads Transmission Program... See Owner's Manual.

Just took it out for a slow spin around the block and didn't see anything come up...just one time where there was, what seemed to be a abrubt downgear from like 3rd to 2nd as I'm going into an entrance.

If anyone has any experience with the slushboxes in these cars...or has replaced the control module...that'd be awesome to hear some feedback.

What a time for something like this to go wrong... :(

[tim]

If this is the first time its ever happened there's still a chance you could get out of this cheap. You need to take it to a shop immediately and have the codes read. You can drive it very carefully in transprog mode (3rd gear), but no more than a few miles to get to a shop.

Possible causes:
Valve body defect
Solenoid
Speed Sensor
ECU fault
temp sensor

or worse:
internal clutch packs
torque converter

One final possibility is that your shifter seals are leaking and your fluid's gotten way low. This is a diy. You should see a very oily tranny pan, and burned up material where the pipes come together behind it. If you have that just top it off with esso or Shell la2634 ONLY!!! (very expensive- call jaggi import-do a search)

keep us posted on any quotes you get and we'll tell you whether they're ballpark.

[MTechnik540i]

If this is the first time its ever happened there's still a chance you could get out of this cheap. You need to take it to a shop immediately and have the codes read. You can drive it very carefully in transprog mode (3rd gear), but no more than a few miles to get to a shop.

Possible causes:
Valve body defect
Solenoid
Speed Sensor
ECU fault
temp sensor

or worse:
internal clutch packs
torque converter

One final possibility is that your shifter seals are leaking and your fluid's gotten way low. This is a diy. You should see a very oily tranny pan, and burned up material where the pipes come together behind it. If you have that just top it off with esso or Shell la2634 ONLY!!! (very expensive- call jaggi import-do a search)

keep us posted on any quotes you get and we'll tell you whether they're ballpark.

Alright, well it had a tranny rebuild at 108 and it's got 130k on it now if that changes anything....and it is the first time it's happened while we've owned it, so like almost a month.

So, just leave it in 3rd the entire time? Or will it automatically throw itself into 3rd.

Thanks so much for the help.

[tim]

If it comes on right when you start it, you are in limp mode- which is third gear- the easiest gear on the tranny as far as line pressure.

[MTechnik540i]

If it comes on right when you start it, you are in limp mode- which is third gear- the easiest gear on the tranny as far as line pressure.

Yeah, it's not coming on now. So, I guess for the time being it's not going to show itself.

As odd as it sounds, could this have anything to do with cold/moisture...the car was left outside last night...and it was quite cold and the car's entire life has been inside a garage. Is there any chance this could be something triggered by the climate change?

[tim]

Yeah, it's not coming on now. So, I guess for the time being it's not going to show itself.

As odd as it sounds, could this have anything to do with cold/moisture...the car was left outside last night...and it was quite cold and the car's entire life has been inside a garage. Is there any chance this could be something triggered by the climate change?

That's why I'm thinking low fluid. The stuff is very temperature sensitive and the case volume can expand or contract by over a liter depending on temperature.

Check that case and pan for me. Do you have a leak?

BTW, even if it doesn't come back on, the error code that generated it will be stored. If the fluid is low, the code will most likely be temperature.

[MTechnik540i]

That's why I'm thinking low fluid. The stuff is very temperature sensitive and the case volume can expand or contract by over a liter depending on temperature.

Check that case and pan for me. Do you have a leak?

BTW, even if it doesn't come back on, the error code that generated it will be stored. If the fluid is low, the code will most likely be temperature.

Yeah, i'm going to check the pan again....if it is the fluid, how easy is it to refill?

Thanks so much Tim.

[tim]

Very easy. You'll need some stuff like a 17mm hex key, a cheater bar, the right fluid, a section of tubing connected to a pump, jackstands or a lift.

Down here in Texas its very hard for the tech's to get the fluid right on the 540 during the summers, where at its coolest, it's at the middle range of temp spec for filling. It's easy in winter, where we can let the cars warm up to the lower end of the temp range, and not have it go through the top end in two seconds.

Before drawing any conclusions, we really need to see that code, or some oil on the pan.

[MTechnik540i]

Very easy. You'll need some stuff like a 17mm hex key, a cheater bar, the right fluid, a section of tubing connected to a pump, jackstands or a lift.

Down here in Texas its very hard for the tech's to get the fluid right on the 540 during the summers, where at its coolest, it's at the middle range of temp spec for filling. It's easy in winter, where we can let the cars warm up to the lower end of the temp range, and not have it go through the top end in two seconds.

Before drawing any conclusions, we really need to see that code, or some oil on the pan.

Yeah, well...we won't drive it 'til next week...and i'll have my friend hook it up to the ECU.

[MTechnik540i]

Yeah, well...we won't drive it 'til next week...and i'll have my friend hook it up to the ECU.

Well, Tim...if you're still following this thread...it seems as it is what you were talking about...there was a little seepage on the base of the tranny...seemed to be leaking towards the back of it. So, thinking it could be a seal or something. Either way, i'm watching it for now on...and a tremendous thanks for the heads up.

[tim]

probably the shifter seal. It's a $1 part. DIY also if you want it to be. If you want to see what I'm talking about, get under the car and look at the side of the tranny case. Up about 8-10" from the bottom, you'll see the shifter linkage. The pin that sticks out a bit goes all the way through and out the other side of the case. Each side has a little rubber seal that is countersunk into the case. It doesn't leak all the time, only when line pressure is high. Sometimes, its not even all the way in. You can use an icepick or the like to pull the old one out, and then use a tube that will fit over the pin, but with an outer diameter that will allow you to push the new one in about 1/2" into the case. Be exceedingly careful not to scratch the pin, or else your leak will become permanent.

Even though its easy, you could combine it with a tranny service and let a tranny mech do it for you. Get fluid (Shell LA2634- 10l to be safe, you'll use about 8), a genuine ZF service kit with filter, o-ring and gasket, and the shifter seals from Jaggi, or Kirt Koeller (do a search).

Did you ever get the error codes read?

Best, and happy NY

tim

[kngpen]

Does it hurt the car to drive around in limp mode? I have a problem with 4th gear or something. Everytime I get on the highway and hit above 55+ it gets the transprog error and goes into limp mode which causes me to be stuck at 60mph@4k rpm. I am pretty sure I need a new transmission and have started saving up. Recently I had to drop about $400 to fix a pulley that broke which caused the belts to come off (they were 2 months old :(. BMW didnt say anything when they had it so....

[tim]

I wish I could help, but I need more info. Does it hurt to drive in limp mode. Well, yes and no. It doesn't put alot of pressure on the gears themselves, but it really stresses the clutch packs for third gear; the band clutch, and other soft parts. As a rule, I say no more than 10-20 miles city or maybe 50-100 miles highway for a car in limp mode- but there's no science or anything backing those mileage numbers. Just gut feel.

[kngpen]

I wish I could help, but I need more info. Does it hurt to drive in limp mode. Well, yes and no. It doesn't put alot of pressure on the gears themselves, but it really stresses the clutch packs for third gear; the band clutch, and other soft parts. As a rule, I say no more than 10-20 miles city or maybe 50-100 miles highway for a car in limp mode- but there's no science or anything backing those mileage numbers. Just gut feel.

Well I recently got a tranny flush, There was alot of metal in the pan. They put it back together and I havent been to fourth gear since. Dont know if its a sensor problem or if I need a new transmission.