Transmission fluid f10 replace or flush?

Bimmerroad · 07-31-2019, 03:55 PM

Do you have an opinion in favor or against flushing lifetime transmission oil?

I am not asking if change "lifetime" transmission oil is recommended, if you research it, you will find out that there are overwhelming recommendations it must be changed , I am wondering if there is any risk to the transmission if flushing as BMW was determined to have it sealed to its early demise.

If flushing is not recommended, what about draining without removing the pan and refill with a cheaper transmission fluid and run the car for a week so the old fluid mixes with the new and then replace the sump, gaskets and fill with the BMW fluid?

Apparently when changing only part of the fluid is replaced.

ezaircon4jc · 07-31-2019, 04:49 PM

Quote:

Originally Posted by Bimmerroad

Do you have an opinion in favor or against flushing lifetime transmission oil?

I am not asking if change "lifetime" transmission oil is recommended, if you research it, you will find out that there are overwhelming recommendations it must be changed , I am wondering if there is any risk to the transmission if flushing as BMW was determined to have it sealed to its early demise.

If flushing is not recommended, what about draining without removing the pan and refill with a cheaper transmission fluid and run the car for a week so the old fluid mixes with the new and then replace the sump, gaskets and fill with the BMW fluid?

Apparently when changing only part of the fluid is replaced.

There's no such thing as a "sealed" transmission. IMHO manufacturers; not only BMW; use terms like sealed and lifetime so they can claim low maintenance costs. I had my 2012 trans flushed a year or so ago at my dealer and will have my 2014 flushed within the next 10K miles or so.

Surly73 · 08-01-2019, 08:39 AM

Drain fluid, replace filter (pan), refill with new fluid and set level according to the procedure no less often than every 100,000km. That's what ZF says to do - not much need to survey the Internet. No need to "flush" (the term can mean a lot of things) if you do it at the proper interval or sooner. It seems that a drain/replace changes a higher percentage of fluid on the 8HP compared to most other transmissions I've worked on. If it's not overdue for some reason, "flushing" can just be asking for collateral damage.

07-31-2019, 03:55 PM	#1
Bimmerroad Enlisted Member 27 Rep 42 Posts Drives: Bmw 550i xdrive Join Date: Jan 2019 Location: New york iTrader: (0)	Transmission fluid f10 replace or flush? Do you have an opinion in favor or against flushing lifetime transmission oil? I am not asking if change "lifetime" transmission oil is recommended, if you research it, you will find out that there are overwhelming recommendations it must be changed , I am wondering if there is any risk to the transmission if flushing as BMW was determined to have it sealed to its early demise. If flushing is not recommended, what about draining without removing the pan and refill with a cheaper transmission fluid and run the car for a week so the old fluid mixes with the new and then replace the sump, gaskets and fill with the BMW fluid? Apparently when changing only part of the fluid is replaced.
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08-01-2019, 08:39 AM	#3
Surly73 Lieutenant Colonel 535 Rep 1,873 Posts Drives: '11 535xi 8AT KWv3 MPE MHD xHP Join Date: May 2012 Location: Oakville, Ontario iTrader: (1)	Drain fluid, replace filter (pan), refill with new fluid and set level according to the procedure no less often than every 100,000km. That's what ZF says to do - not much need to survey the Internet. No need to "flush" (the term can mean a lot of things) if you do it at the proper interval or sooner. It seems that a drain/replace changes a higher percentage of fluid on the 8HP compared to most other transmissions I've worked on. If it's not overdue for some reason, "flushing" can just be asking for collateral damage.
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