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Transmission Flush at 100,000 miles?

23K views 33 replies 20 participants last post by  gttriley 
#1 ·
Hi there,

I have been debating for some time whether I should do an automatic transmission fluid change (including filter change, obviously). I have a hair over 100,000 miles on my 2001 325i and am planning on keeping the vehicle for as long as possible (would love to hit 250,000 on it).

I currently do not have any issues with the transmission, except in third gear the RPM's will dip about 300 upon acceleration then continue to rise. (Much like a gear shift, but without actually shifting gears). The dealership told me this was normal about 40,000 miles ago.

Should I change my tranny fluid?

Thanks,
Mike
 
#2 ·
There is no such thing as lifetime fluids. Do search and you will see a bunch threads on this topic. Read some of the links below, but I am sure there are more. I flushed mine at 95k and I will be doing it every 30k-60k depending on when I can perform them. GL

http://forum.e46fanatics.com/showthread.php?t=389974&highlight=steptronic+transmission00

http://forum.e46fanatics.com/showthread.php?t=366147

http://forum.e46fanatics.com/showthread.php?t=126486

http://forum.e46fanatics.com/showthread.php?t=438667 DIY GOOD INFO.

Hope this helps.
 
#22 ·
:woot: Makes me happy someone linked to my DIY thread!

there's really no right or wrong at this point.

either way is risky. people have already posted that they've changed the fluid after 100k+ miles with no problems. other people have done it and regretted it.

perhaps you could drain & refill it little by little over a few months? sort of like a fishtank, i guess. you cant change all the water all at once, or it could shock the fish & kill them or whatever.
Drain and Refill little by little is a BAD idea. It seems to be a safer method but keep in mind, you can't replace the filter unless you drop the pan. Changing fluid without filter = :nono:

If you change the fluid without the filter the new fluid has detergent qualities which could dislodge grime and clog the old filter. This is why you always change the two together.

I would definitly go for the change if you aren't having tranny problems! Now is the best time before they start. I did it at 93K, look at the diy I put most all information in there.

Goodluck! :hi:
 
#3 ·
BTW What does 100,000 Miles equal out to in KM's???????????????
 
#7 ·
Interesting. I took mine (with 130K miles) in to the dealer for an oil change/brake flush last week and asked them to do a tranny flush as well. They outright refused to do it, saying that the transmission fluid is lifetime and that flushing the old fluid could actually cause more problems than not changing it. I've never heard of a dealer's service department actually turning down requested work-- they usually recommend everything under the sun, necessary or not!
 
#9 ·
Interesting. I took mine (with 130K miles) in to the dealer for an oil change/brake flush last week and asked them to do a tranny flush as well. They outright refused to do it, saying that the transmission fluid is lifetime and that flushing the old fluid could actually cause more problems than not changing it. I've never heard of a dealer's service department actually turning down requested work-- they usually recommend everything under the sun, necessary or not!
Go to an independant then.
 
#8 ·
How come my car doesnt have Miles on the speedometre i live in Canada?????????????
 
#10 ·
I asked a well known indy shop in my area and he said that if you don't change it before 50k you're better off leaving the fluid in there. He said he didn't find a correlation between changing tranny fluid every 50k and tranny longetivity. In other words, he saw trannies that had the fluid change break down before 100k miles and trannies that are running strong w/o a fluid change. Go figure. Basically he said, it's a crap shoot.
 
#12 ·
I got the same story from 2 indy shops in my area. But I just don't believe that fluids in between high velocity metal pieces can last the lifetime of most of the rest of the car's parts. So I picked one of those shops to change the fluid @ 70k (mostly highway), and they updated the step software too. 2 dealers in the area refused to change the fluid.
 
#14 ·
changed at 100,000 mile a couple of years ago. I don't do a flush, just filter and drain(5 qts). This is the information I understand:

A long time ago when dextron III came out. GM said that the new formula will last 100k and that oxidation is the reason for it to break down( I'm guessing the GM also assumes that the tranny will not overheat and stuff). So, if it sealed then it should last forever(lifetime). Do you trust it? I don't.

Your point on changing the fluid.
Change the fluid now and risk f-ing it up. The tranny may last 200k w/o it. My thinking is that if you don't change the fluid, for sure it's going to f up. It's also a peace of mind too for me.

I'm consider draining it again soon. With no filter change, bc the first time things look Ok.
 
#17 · (Edited)
there's really no right or wrong at this point.

either way is risky. people have already posted that they've changed the fluid after 100k+ miles with no problems. other people have done it and regretted it.

perhaps you could drain & refill it little by little over a few months? sort of like a fishtank, i guess. you cant change all the water all at once, or it could shock the fish & kill them or whatever.
 
#19 ·
If your transmission is working fine, now is the time to change the fluid and filter. Draining the transmission, dropping the pan, changing the filter, and refilling to the fill port with the transmission up to proper temperature (around 100 F) will not change ALL the fluid anyway.
Use the right fluid. I have researched and researched this trying to rationalize how I could use Dextron 3h instead of Texaco expensive stuff. Yesterday when picking up my 99 323 from the transmission shop (remanufactured this week) I spoke with the German owner / master technician who insisted I only use texaco because of the specific additives that are necessary for our transmissions (in my case 5L40E GM) as used in the BMW. Other people will share anecdotes about successful use of something else, but having just trusted my transmission to this guy to rebuild it, and this is what he does for a living, exclusively, I will respect his opinion. He also said change the fluid, maybe every other year or even third year if you don't drive much, but lifetime is the demise of these transmissions.
 
#27 ·
Just to be clear, is changing the transmission fluid only controversial for automatic transmissions? I'm a little over 100k and I don't think the transmission fluid has ever been changed, but I have a manual transmission. Should I worry about changing the fluid?
 
#33 ·
Your car and mine are basically the same. I changed my ATF a month ago.

Yup, the pan screws are T27 and the filter screws I think are T30. Although torquewrench did an awesome DIY, lesson is not to follow all posted DIYs to the letter, but to treat them as guides and adjust to your own situation as necessary.

Improvisation is a must sometimes. In my case, I didn't have access to an automotive fluid pump, so I just improvised by using a pressurized plant sprayer and some vinyl tubing. Worked for me and gives that satisfaction of being a DIYer.

I changed my ATF at only 30K miles, but still felt some improvement on smoother shifts (it was working fine before anyway). More importantly, I was glad I changed it since I put about a liter more in (following the 40degC running-engine routine) than what came out. Saw some threads here where their ATF was severely underfilled when they checked it.

What mileage did you change yours? Noticed any drastic improvements?
 
#34 ·
I did mine at 82,000 miles. I didn't really experience any drastic improvements, although I don't think mine was underfilled as you say yours was. It was shifting fine before. This was strictly a preventative maintenance procedure. I think I'll be performing a simple drain and fill in a few more thousand miles, since even after removing and replacing about 6.25 liters of fluid, it still looked pretty dirty. After another 30K, I'll drop the pan again and replace the filter as well. By the way, I found a post on x5world.com stating that you can buy Esso LT71141 for $10.34/l. That's cheaper than I got the Pentosin for, but will probably come out to be a little more expensive once shipping is added. The place is called Europarts in San Diego www.europarts-sd.com .
 
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