CleanIsFast Journal: BMW X5 4.6iS

[CleanIsFast]

Cabin filter replaced (amazing how big it is). Still waiting for a day to get underneath the beast and possibly top off the transmission fluid (if needed). I also ordered a blackstone oil lab kit for next oil service. Possibly get a quick oil analysis to see the relative health of the motor without dropping the oil pan.

Vehicle still pulls like a freight train. No real chain slap or "marble in can" noises at all. I have a startup squeal from the starter so that'll have to be replaced sometime soon. A bit embarassing having the startup squeak in public...Other times it starts up perfect - super quiet.

[CleanIsFast]

Okay these quotes are from the 4.6iS Registry thread. I didn't want to muddy up that thread about transmission woes.

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Originally Posted by dannyzabolotny

Before you drop the oil pan and replace the heat sensor, plug in some kind of real time scan tool that can read the transmission temperature. If the sensor is on the fritz then it'll show some crazy number. My 540it had that issue in the winter, it would show the transmission temp as 130ºC after sitting all night! Now if the transmission temperature sensor is working and showing a correct number (as in, it starts cool when you start the car and rises as you drive) then that's not the issue. If the sensor starts showing a really high temperature when the car is at operating temperature, then you might have other issues like a bad transmission thermostat or a bad transmission heat exchanger. That's a very common issue with the early L322 Range Rovers (same M62tu and 5HP24).

Originally Posted by bcredliner

Symptoms are somewhat random shifts and sometimes will downshift from 5th to 4th or 3rd when you are cruising. I used infrared temp reader for verification and read OBC for error codes and saw I had the associated code. I don't think the 2-1 is a symptom of temp sensor and even if it is that is also a symptom of other issues.

Originally Posted by jopecasa

Have you tried clearing transmission adaptations via INPA?......might help.

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Basically just need to get some software and look at the readings. But here is another wrench I'll throw in that I noticed today and it was a bit shocking.

So it was about 95*F yesterday so obviously I had the A/C on in the vehicle. I noticed on the way to work that the 2-1 downshift lurch wasn't there anymore. Completely gone, baffled...Then I thought to myself "well maybe the vehicle didn't get up to normal operating temperature 100%" - which could be possible since it's only about a 12 mile drive to work.

Figured I'd see if the same thing occured on the way back home that evening. Same scenario, blazing outside, A/C on. This time stuck in DC metro traffic (car fire on the highway), two lanes were closed off so it took a lot longer to get home. Vehicle was definitely up to normal operating temperature. Again, the 2-1 downshift lurch wasn't there...So, once I got off the highway I turned off the A/C and continued to drive as normal. Lo and behold...it came back!

My assumption, the A/C unit when on keeps the rev's slightly higher which 'somewhat' cured the transmission 2-1 downshift??? I highly doubt the A/C is cooling the transmission or transmission thermostat. This brings me back to - when the vehicle is in 'sport mode' the 2-1 downshift lurch is not there at all either. My assumption is that 'sport mode' keeps the rev's slightly higher as well. But the 2-1 downshift isn't present until 'normal operating temp' as well, any temp before and it's not there at all.

Maybe my vehicle is idling too low? Maybe I can program the rev's to be slightly higher?

[bcredliner]

The transmission operating temp is reached in very few miles or idle time. I don't think idle or A/C is part of the problem. I doubt that it has anything to do with trans temp. But, as suggested, use a infrared temp tool to read trans fluid temp cold and let it idle for 10 minutes and read it again. Normal operating temperature ranges from 176-212 F. Start by reading temp, easiest and cheapest thing to do. It is not unusual that the 2-1 rough shift does not happen in sport mode.

[dannyzabolotny]

What you're describing is quite common, actually. My 540it had the 2-1 downshift lurch when I bought it last year, mostly because the seller kept the AC off. Once I turned the AC on I never experienced that shifting issue ever again. I keep my AC on 24/7/365 so that's a permanent fix for me.

I'm sure if I went outside and drove my 4.6 with the AC off I'd get the same downshift lurch despite having a rebuilt transmission with a new torque converter.

[bcredliner]

That's not normal, problem is still there just masked. Air conditioner on is just covering it up.

[CleanIsFast]

Originally Posted by bcredliner

That's not normal, problem is still there just masked. Air conditioner on is just covering it up.

I agree, just seems very odd

[andrewwynn]

Get some actual temp of coolant. I had some horrible engine performance problems when my thermostat soft failed. I only knew it failed when the ambient temp dropped low enough the heater no longer warmed the cabin. Turned out my thermometer effectively opened at 65C vs 90C and because of the utterly moronic non gauge that looks like a gauge but functions like an idiot light (by snapping to 12 o'clock position between 60 and 110°C) it's worse than useless for determining anything useful. Use hidden odometer functions to read engine temp and if possible oil or transmission temp


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[CleanIsFast]

Originally Posted by andrewwynn

Get some actual temp of coolant. I had some horrible engine performance problems when my thermostat soft failed. I only knew it failed when the ambient temp dropped low enough the heater no longer warmed the cabin. Turned out my thermometer effectively opened at 65C vs 90C and because of the utterly moronic non gauge that looks like a gauge but functions like an idiot light (by snapping to 12 o'clock position between 60 and 110°C) it's worse than useless for determining anything useful. Use hidden odometer functions to read engine temp and if possible oil or transmission temp


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Coolant temp is good, I checked to make sure my thermostat was working properly. I checked the secret menu (option 7 I believe) and thermostat is in proper working order.