TRANS.FAILSAFE PROG | HELP!!

[portlandia]

Hi guys, I have a 2002 BMW X5 4.4i 160k miles on it.

It's a beast and it impresses me every time I drive it until recently.

One time, as I was going home. Everything was fine, then I suddenly felt like I was dragging something. I pulled over at a gas station and everything seems fine. I revved it good and sped up good. Everything was going great until the last stoplight before home. As I accelerated from the stop light, the car seemed like it had a sliding clutch. The car was shaking and the gears seem to fail to engage. It revved over 5k rpm on Drive with nothing happening until the "Trans.Failsafe Prog" popped up a good 7 seconds later. The car seemed to be stuck in 5th gear and can drive just fine on that mode, just not the accelerating part.

After restarting, the failsafe is off but the SES light is on. I tried driving normally but every time I rev beyond 1,500rpm, the car just shakes and won't cooperate until the failsafe prog comes up again and I'm back in 5th gear.

What's weird about it is that when the program is not engaged, I could not do much with Drive, but Reverse seems to be very responsive.

It's 100F here, right now, so I doubt it's the cold like some people suggest. Please help. I've read some people attribute it to DSC modules and alternators, but they seem to have never experienced the shaking and sliding scenario.

Please advise.

[tmv]

check your battery and alternator.

[Big "J"]

Sounds like you're experiencing what a lot of us have or will, tranny is dying. Take it to a reputable shop and get it checked.

Good Luck!!

[SlickGT1]

Check the bat and alternator first.

Any noise when accelerating?

[civdiv99]

Trans computer monitors input and output shaft speeds (nothing fancy, just a sensor that outputs a frequency), and compares this to expected relationship based on what it told the trans to do. For example say it calls for third gear, but since doing so is only changing pressure solenoids, it relies on the feedback of shaft speeds to determine if orders were carried out, and also how quickly.

I'm simplifying here, but in general, if it doesn't see what's expected, it'll try the next gear, etc. until it doesn't perceive a slip. Included with this is usually default to max pressures, etc. in an attempt to not strand you.

So the thing is, when a certain thrust bearing begins to fail, the trans cannot hold clamping pressure on the "A" clutch, and under even moderate load it will give way (slip). This clutch is used in gears 1~4, so when this is happening, you end up in 5th. After shutting off for a very brief period, the trans will try again as if all is normal, even though the SES light is on (fault code set). Almost certainly the code will be one if the trans codes reflecting implausible relationship related to a given gear ratio. It can throw you off sometimes since you can read and reset the code, and next time same behavior but different code is set. But that's just because as this is failing, the slip and fault may occur in a different gear than the previous event.

IF this is happening to you, you are in a populous club indeed. Standing room only. So go forth and check the usual suggestions; such investigatory steps are generally painless, but do prepare yourself.

Read through the various posts on this topic (there's plenty), and note there are also a number of ways to approach the repair. Warning: BMW dealerships don't fix, they replace, and for some reason generally charge a hell of a lot to do so. Others have used independent's to handle the whole thing; some I know handled the removal & replacement but did an exchange to obtain replacement trans, and a number of us have popped it out, disassy and replace parts, reassy and reinstall.

So go through your deductions and get opinions (note - opinions from dealerships or repair facilities are not unbiased, no matter how honest the facility, simply because they are in business to provide a service). Ya just gotta deal with it all.

[portlandia]

Thanks for that. That was very informative. Is there a good chance that it may be just my sensors? And if it is, is a teardown or disassembly of the trans required to install it?

[civdiv99]

If shaft speed sensor was faulty you would have a trans fault all the time. It's just a magnetic sensor located to read off of a toothed wheel.

Trans do better when it's cold (relatively speaking, like on a morning start off vs. after driving)?

The slip and fault happen whether in manual mode or auto? (note: manual mode isn't manual, it's just a way for the driver to respectfully request a different gear. Changes are still regulated and approved by the computer committee.)

[GOFAST GUY]

This is all SOOO true to what I"m going through right now. These replies just help me to understand more about how much transmission is failing and what needs to be done. It's too bad there aren't replacement that make the problems go away altogether, but a least we know what the future has in store.

Thanks

[portlandia]

An interesting update. I've been trying to get in touch with a decent transmission place over the holidays to no avail. BUT NOW, all of a sudden, my car's been doing great! No knocks. No lags. No error program. SES is still lit, but other than that, my car's great! Hopefully this isn't a fluke. I'll still have it checked one of these days. But at least, now, I know it's not a mechanical problem, and I thank God for that!

[Randy123]

Hello All, newbie here. I have gotten some good advice off the forum here and wanted to share this.
Here is my story on the Trans fail safe light. You might not believe me..but true...at least so far. Knock on wood!
I had the trans fail safe light come on sporadically over the past 12 months. Sometimes the Brake warning light and yellow triangle looking light also. Always reset after stopping and restarting. Well it seemed to get worse after a very long trip to Texas. One day I got a check brake light bulb (bulb out). Indeed upon checking, the right brake light wasn't working. I pulled out the bulb, but it looked fine. Went to ORielly's to get a new bulb. I decided to look it up in the book first. GLAD I DID! The bulb listed (can't remember #) was not what I had in my hand! Hum... I bought the bulb listed and installed. Check Light went out, brake light works...AND I have not had the trans fail safe, brake warning light issue since!
Note: when I pulled the incorrect bulb out- it was so hot I couldn't hold it with my bare hand! The brakes were not applied for an extended period either. I bought X5 used and the wrong bulb must of been installed by them or their mechanic.
I'm guessing that the wrong bulb was causing a voltage or resistance issue somewhere (DSC ?) and that was causing the problem. BTW, my brake bulb circuit board seems to be fine. Wish I kept the wrong bulb to tell you wrong one installed. More important is to make sure correct number is installed.
I hope I didn't jinx myself but after about two months and several 4 hour drives in the Texas heat- no issues. Based on the last 12 months..I would definitely encountered the issue again by now.
Check all of your brake lights for the proper bulb! Doesn't take 5 min and it might just save you big $$. That's my story and wanted to share. My fingers are still crossed


2003 X5 3.0 GM Auto Trans 110,000 miles