CleanIsFast Journal: BMW X5 4.6iS

[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.