The Verdict Is Here: E46 Auto Transmission Fluid Change (Pics and Lab Report)

Disclaimer: Say what you want about the person. You can call me an guy who is too persnickety about my car, a guy with too big of an ego, a good guy, or a genuine jackwagon. However, DO NOT question the facts that come out of my mouth, that have been simply relayed from one source to another. I have spent over a dozen hours just reading up on threads about changing the transmission fluid. Some rely on witchcraft for information, others on common sense, and others on technical literature. After eliminating the outliers, I decided it was time to take action. The findings in the post are for my account only. It may inspire others to change their fluids, but please note, that some people's transmissions have failed due to messing something up during installation, or by using the wrong fluid. DO NOT CUT CORNERS ON THIS PROJECT. I did not DIY, but rather took it to a locally famous transmission shop, and it was done in two hours. No problems since. Afterwords I have felt smoother shifts, less gear shock, and no more over-revs when the car tries to find gear. If you want your BMW to last longer, to perform better, and to have better peace of mind, THIS PROJECT IS A MUST. My findings are below.

Since the beginning of time, or since the beginning of the E46 run that is, owners of these beloved BMW's have been wondering whether or not to change the transmission fluid.

The answer is YES. However, with some caveats.

30,000-50,000 Miles =No Need to Change
50,000-75,000 Miles =No Urgency, But Won't Hurt To Change
75,000-100,000 Miles = You Should Change It, Won't Hurt If Not
100,000+ Miles = Change it as soon as you get the time and money for CORRECT Parts.

If you want to DIY, clear up an afternoon (in case anything comes up), and get yourself some jack stands and a crawler. You're in for a grease filled day.
If you want to take it to a shop, make sure it is a reputable shop that wants to do it. Some shops differ lifetime fluids in order to dodge a lawsuit (I guess, I'm not a lawyer). The pan MUST BE DROPPED, and MUST BE CLEANED for full effectiveness. Make sure your shop knows.

Then determine what transmission brand you have. ZF or GM are the two only options. Then find out what specific model it is. From there, find out what fluid it needs (DON'T BUY THE CHEAP STUFF.) Compatible fluids can be swapped out, but make sure it is certified.

The cheapest and most reputable place to buy the Filter Kit, Extra Bolts, and Fluid was from the California Transmission Supply Company.

www.thectsc.com

Fantastic service. For my filter kit, the most expensive fluid (and probably the best), and 10 extra bolts was $175 after shipping.

My Fluid.


Scheduled a date at the transmission service company and took it in.
$133 was for 1.5 hours of work, plus a road test and double check after road test. Everything was fantastically done.

My car at the shop, Yo!


Grand total- $308.
Satisfaction-10/10
And also extending the life of my car dramatically!!

I also felt like the big guy on E46 Campus, so I decided to send a sample of tranny fluid to Blackstone Labs (Google it!). For $25 they analyze the fluid and tell you if it needed changed, was good to go, or if your tranny is about to skip town and disengage from the car.

Here's zie gran report! Drum Roll.....



And the verdict is.....NOT LIFETIME FLUID! Not a surprise though. Lifetime fluid was just added on our generation so when buyers went to the dealer to look, the service cost was dramatically lower than that of Audi and others because tranny fluid supposedly never needed serviced. (So I guess that made you spring on the deal? Yeah I'm sure that ever happened.) Also, the guy at the transmission service center said that BMW Considers 100,000 miles one lifetime.

It's life after death for me!

great info. I changed mine at 116K, now its close to 130k no problem what so ever.

Can I use ATF for manual transmission?
For $5 a bottle it seems pretty cheap maintainence.

I have had redline MTL in it for 3 years now. First gear is getting difficult to shift into.

I have no experience in Manual Transmissions so I cannot answer your question Merc. I would say No to ATF in manual. They make MTF for that. I think the popular brand is Redline

I thought the gears in manual transmission would lubricate using just about anything.
It should be a lot robust than auto transmissions

so this thread is about whether or not the BMW auto trans fluid is "Lifetime"? i didn't think anyone still argued/thought it was. BMW has posted it to be 100,000 mile for some time now. and most suggest 60,000 mile intervals to insure longevity of those automatics.
the Diff fluid is also not good for a Lifetime.

i as a Fanatic like to thank you for taking the time/money to send to Blackstone Lab. nice work on posting your lab results.

Great work Sweetness!

Thanks for sharing.
Good and right job done

Lifetime fluid is a snake oil!

If you never change your ATF fluid, when your trans fails, it will have lasted for the lifetime of the transmission! So from that standpoint it is not snake oil, it is "lifetime" fluid.

You absolutely need to change your trans fluid. The friction additives break down and oxidize with heat over time. Plus the filters do no remove all the abrasive particals.

If you ever overheat your engine, assuming you do not blow a head gasket as it will consume your time and money fixing that, you need to change your trans fluid as there is a linear lifespan relationship with ATF when compared to temperature.

The higher the temperature, the shorter the lifespan of the fluid. As I recall 250F will render the trans fluid life to about 25k miles.

Also the type of driving will also dictate how long your trans will live. Think of it based upon total number of shifts. So if live in a rural area and drive mostly highway routes, your trans may only 100-200 times a day.

If you live in the city and drive in a lot of stop and go traffic, your trans may shift 200-800, or more, times a day. So you can see where the type of driving can directly impact your transmissions lifespan.

Heck, when I drive 4 miles to the grocery store and my trans probably shifts about 25 times due to the number of short streets, stop signs and stop lights.

OP, i just ordered the oil and filter kit from the same vendor, i didn't see see a kit for the 10 replacement bolts. I was hoping to get my stuff before this weekend to get it serviced, but the filter came from their california office, and oil is coming on tuesday from their chicago office.

I really need to count the number of shifts I do with a manual. 200-800 shifts sound like a good work out.

My M5 has 3:45 rear gears, so I typically start in 2nd gear and many times do what I call the evens. 2, 4, 6th gear, and I can drive around town in 6th gear at 40 MPH no problem.

Sometimes I just hate "rowing" the boat all day!

It amazes me how my M5 can go from 40 to 190 MPH in just 1 gear. Gotta love the double Vanos and 7000 RPM redline!

It's not something new, and the verdict has been given long time ago. Many expert advice on this too. Even BMW says: change every 100k that seems to be absolutely right. I changed mine with factory fluid at 98K and it still had some life in it but I'm glad I changed it. A number of VERY important points is missing in this post. Such as mixing different types of ATF and the importance to drain and fill. It could be ok to change the type/brand of ATF only if you manage to evacuate ALL the fluid, if you mix you'd better put the factory stuff in, such as ESSO or TEXACO fluid. A lot of "expert" advice now everywhere. Too bad.

Good luck.

The real problem here is that you own a car with an Automatic Transmission...

thanks everybody!

The screws I got for my transmission,
http://www.thectsc.com/index.php?p=p...d=196&parent=3

Originally Posted by MercForHire

I thought the gears in manual transmission would lubricate using just about anything.
It should be a lot robust than auto transmissions

actually no. some transmission with brass syncros cant use GL-5 gear oil.
if MTL is too thin for you you can try MT-90

Originally Posted by Imola.ZHP

The real problem here is that you own a car with an Automatic Transmission...

Beauty is in the eye of the beholder, but you and I love the same girl!

Does the website you posted only carry stuff for ZF trannys and not GM ones?

My daily vitamin has more chemicals than that on your report. Beat that.
"Verdict" is too strong a word for you or for anyone to use on the auto tranny oil issue.


And how come no one has ever come forward to report their auto tranny failed due to not changing their tranny oil?

Originally Posted by Hoebama

And how come no one has ever come forward to report their auto tranny failed due to not changing their tranny oil?

How do you know every auto transmission failure is not due to fluid failure?