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      09-04-2017, 09:49 PM   #1
PortlandWineGuy
New to BMW ownership
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Drives: 2010 black 128i auto
Join Date: Apr 2016
Location: Portland, OR

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Auto trans fluid for HPDE?

I'm wondering if I can/should use a high temp/racing transmission fluid in my daily driver that occasionally sees track days/nights; just 2-4 per year.

Details:
128i N51 ZF automatic transmission, 120k miles
Eibach springs, koni adjustable, continental extreme contact sport, aFe filter, high temp brake fluid, cool carbon brake pads.

I bought the car with 88k miles, no maintenance records so proceeded to replace all fluids including trans and diff fluid. Did 3 or 4 SCCA track nights in summer 2016 after purchase, and another 3 track nights (each with 3 20-minute sessions at full pace) so far this year. Although it never threw a CEL, the car would suddenly stop revving up easily and lose almost all power after 10 to 18 minutes of HARD (95-100% of limit) driving. Figured out that it's the auto trans overheating. Ran with electronic aids on trans turned completely off (press and hold traction button). Running heat on full blast with closed center vents and side vents pointing out windows kept it from happening until the 18th minute of my 20 minute sessions this summer. After cool down I could do another 15-19 minutes before it would happen, depending on heat of the track/day.

Now that I've boiled/overheated the trans fluid on each of these sessions and ran it 30k miles, should I replace the fluid now or wait until spring (40k miles), before my next track days/nights? I'll probably only do 3-5 track nights and days next year. If this keeps happening I might only do track nights. If I can resolve it I'd try a full day.

Should I try using a higher temp auto trans fluid (ATF)?

Before the trolls come a trolling: I'll buy a dedicated track toy as soon as I can afford it. Until then my DD serves dual use.