Thank you Xoutpost! Trans.Failsafe. Program

[Kev]

Just a quick post to thank you all for a good night's sleep last night

About a year ago, the gearbox in my UK spec 2003 3.0D completely died with absolutely no warning. One minute driving perfectly. The next I was going up a hill and the engine just revved to the redline but the car could barely move. First time I saw the message TRANS.FAILSAFE PROGRAM. Turn off, cool down. Few hours later drives a few yards and then slips like crazy and wont pull at all.

Trusted Indy Diagnosis. Not electrical, or speed sensors (as hoped), nope, complete recondition of the gearbox. Cost me about £1800 (the same week I was due to sell the car to move to Italy.).

Almost a year later. Now living in Como, and driving a 2005 3.0D (this time with the 6-speed Auto). Its just started snowing. About -3 outside and the wife calls me. "Car wont go". Some error message about TRANS.FAILSAFE PROGRAM.

Sh!t - lightning does strike twice! The car has done about 130k km and is more or less perfect. I say more or less cos at around 60kmh in 6th gear I feel a little blip every 5 seconds. Speed up or down +/- 10kmh and it disappears. Change to 5th gear (ie. up the revs) it also goes. Hmmm, must get that checked methinks.

Anyway, got to the car, and the car wont even start. Looks like a flat battery, I get all the flashing dash lights when I try to start, but the end message, glaring at me is, TRANS.FAILSAFE PROGRAM. How stupid is that?!? Why not put up a message like BATTERY VOLTAGE TOO LOW ???

Get home. Get straight on Xoutpost and my mind is immediately put at ease. Electrical, battery, alternator, or even DSC. Not a new gearbox anyway. Probably having seen the symptoms of a real X5 gearbox failure just a year before also made me realise that this was different. In the real f**ked gearbox scenario the engine starts just fine, its the pulling away when the problem is obvious. Anyway, next morning, battery fully charged, the car goes like a dream

But this blip? I even thought it was my imagination - being super paranoid after the last gearbox croaked. It's there. My friend also felt it. Its just for like a quarter of a second, like a cog slipping/missing or something, but can't be as its only every 5 seconds.

I'll get it into BMW this week (I really miss my UK indy now I live in Italy) to see if there are any error codes showing but it was checked 6 months back and the only errors were about the glow plugs.

I'm really tempted to ask them to change the tranny oil. I know there are mixed opinions on this - but I think that at 80k miles it would be better to prevent than cure a serious gearbox failure. Can anyone actually agree with the theory that changing the 'lifelong' oil will disturb the metal particals that are gathered in the crevices of the transmission and actually cause rather than avoid problems?

Sorry for the long post - it's been a while

[SlickGT1]

I did a drain and fill on the oil, twice. Once with new filter. So far so good. knock on wood. Quite a few others did it as well with no negative effects. I wouldn't flush the oil though, just drain and fill.

[Kev]

Thanks. Hope I can explain the difference to BMW Como. Makes a lot of sense actually

Kev

[JCL]

Originally Posted by Kev

I'm really tempted to ask them to change the transmisison oil. I know there are mixed opinions on this - but I think that at 80k miles it would be better to prevent than cure a serious gearbox failure. Can anyone actually agree with the theory that changing the 'lifelong' oil will disturb the metal particles that are gathered in the crevices of the transmission and actually cause rather than avoid problems?

It isn't the metal particles, those are filtered out by the pick-up filter. It is more so the sludge that has settled in the valve body, mostly made of non-metallic clutch friction plate material, baked in place over time, sitting there and not really hurting anything. Until there is an extreme amount of it.

Transmission fluid has a very high amount of detergent in it, by design. So over a long period of time, the detergent (additive) level decreases. Some contaminants build up throughout the transmission. It happens. Then when you introduce a new, clean, but more importantly high detergent, fluid into your transmission, you clean it all out. You shock the system, basically. All that stuff that moves around doesn't get removed from the transmission, because you have already sealed it back up. It gets redistributed. And if any of the very small pieces block a passageway in the valve body, you can get problems. That is the failure mode.

We can call it a theory, but it is a very well documented failure mode that has gone on for decades now. It is not at all assured that it will happen if you change the fluid, but it can happen. And when it does, those of us who have seen it more than once think to ourselves, how sad, too bad.

So, if a transmission was shifting fine at 130,000 km I would leave it alone, because the benefits of clean fluid are balanced out by the risk of changing it.

But if I had a shifting problem, and wanted to try a fluid change to see if it helped, sure, why not? In that case I would consider that I had little to lose. If the transmission failed subsequently, I wouldn't put it down to the fluid change, because at worst the fluid change would have accelerated the failure that was already coming on, it wouldn't have caused it.

People think about transmission fluid as being better because it is new, but they are only considering contamination. They need to consider all the characteristics of the fluid. Also realize that new fluid will have different viscosity than the oil fluid. Just like Dex IV has different viscosity than Dex III, new fluid is thinner than old fluid (which had dissolved material in it). Thinner fluid could shift better, or worse. Depends on your transmission and how it responds. for example, if something is partially blocked, a thinner fluid may improve it. However if something is leaking past a seal, a thinner fluid may worsen it. Won't know until you try it.

Your blip sounds like it may be related to the lock up torque converter. There is a solenoid, a valve body full of passageways to control the clutch, and then the clutch itself. Releasing and re-engaging would feel like a blip as you describe it. Just a theory.

[Kev]

Hey, thanks JCL for taking the time to explain so clearly and logically the "theory" that I had until now just about understood.

Your theory on the torque convertor also makes sense but could it be diagnosed without stripping down the gearbox? Are there likely to be any indications from the diagnostics? The car should go in for its next oil service in a few weeks (Inspection II was 11 months back). Maybe I could ask them to run a full diag test?

Thanks again, although I'm still no more decided on the next course of action - don't really like driving around with my fingers crossed

Cheers, Kev

[JCL]

You need someone trained in gearbox diagnosis to do that diagnosis, not a BMW dealer that has been told by BMW that his only option is to replace the transmission. Well, he can do a few small things, but not much.

There are electronic diagnosis tools, and then there is the valve body to look at, before planning a gearbox overhaul. Not saying it may not need an overhaul eventually, but no sense jumping in the deep end without determining if something simpler can help first.

[Roadkill]

Kev, i have the exact same "blip" that you are describing. it's been prevalent and undiagnosed for roughly 6 months until now. i took my car to a local trusted tranny specialist (bmw/benz) and he told me it was a failing shift solenoid. best case scenario was to let it die and then have the warranty company replace the transmission. other than that, he told me the warranty company won't do squat. fast forward to 2 weeks ago. i was at a friends shop and he had just hired a new bmw master tech. this tech noticed what i was driving and asked me how i liked it. i told him i really liked it aside from this failing shift solenoid. he asked me what the symptoms were. i told him it was a very brief jerk at around 30-35mph but it would go away if i accelerated or took my foot off the gas. he asked me to drive around the block and when the car began to jerk depress the brake pedal very lightly just enough to illuminate the brake lights and hold it there. guess what? it went completely away. when i got back and told him, he explained that the problem had nothing to do with shift solenoids. we have failing torque converters. as you are driving and step on the brake pedal, this action locks up the clutch in the converter and prevents that jerking. so, i don't know if this helps your situation but at least it may shed light on what is going wrong. my personal situation hasn't changed in that i am still waiting for a failure so the warranty company can replace the transmission and converter but at least i know what's going on. good luck