CW, Come on man don't list prices or my wife will figure out how much I have spent!! I don't want all my food to taste like almonds [emoji28].

I'll find the email for the new old stock of e61 parts and hope that you don't "slip" and fall into the pool if your wife sees that post[emoji1696][emoji1787]

Sent from my SM-A730F using Tapatalk

I changed the oil to the Valvoline long life XL oil suggested above and when I put it in right away its 20% better. 300 miles so far and its about 40-50% better.

It will never be 100% but I would never use the BMW ZF fluid. Here is a tip, fill the trans until it just starts to run out, start the engine in park at idle. The dripping stops and you can get in about another quart until it runs out again when the engine is running.

A couple post in this thread say to replace the shift O-Rings
? I'm not sure what that takes but it probably is the problems I'm having now. I wish someone would post how to replace them.

Bottom line: On a E53 DON'T CHANGE THE TRANS FLUID. The fluid was about as nasty as it gets coming out but it shifted fine.

If I had a similar situation I may look into AT-205 treatment. If the sloppy shifting is from the seals getting hard that stuff is supposed to make the rub we softer and seal better.

In fact I'm planning to get some and may try before I do the filter change on wife's X5

Good info Rockit. Thanks for the update. I'll add that I just used liquid moly's substitute for the zf lifeguard 6 that these trans call for. It is also very thin. If I hadn't changed the bridge seal and the 4 rubber sleeve seals I'd be very worried.

This was on a 186000 mile 6hp19 in a 5 series wagon. I am still in the process of the fluid fill (got 3.5 liters in so far) as I was waiting for a guibo, exhaust gaskets, and csb to come in before continuing on the trans. Will update with results here to add to the knowledge base. The vehicle had no real shifting issues before the work.

The 5L40E originally came with something similar to Dexron III, so it was likely much more viscous than the Dexron VI that most are currently using. I changed mine out with the MaxLife fluid which I swear used to be a bit more viscous than Dex VI. After I had changed it out, I happened to look up the specs and it now says it's actually slightly LESS viscous than Dex VI. Unless I'm mistaken, it appears they have changed the formulation sometime in the past couple of years resulting in a lower viscosity.

It seems to be working fine in my trans, so I'll leave it in there for a while, but I may try something else like the Castrol Multi Vehicle mentioned earlier at my next fluid change. I'm not in the camp of those who believe in old, contaminated fluid being the ticket to long transmission life.

AM.

I did a total of 3x drain and fills with DEXRON VI within a few k miles of getting my 2001 3.0i. Had ~160k miles on the original fluid when I started. No problems, and very glad I did it. Smoother, faster shifting. Did it carefully, which I posted on this site back when I did it.

On the DEXRON VI vs. III, I believe the low temp viscosity of the VI is lower, and you can pretty easily see/feel this when you pour it in. But the VI is more stable, retaining the viscosity both with temp increase and with wear. So as the fluid actually operates in your AT, at temp, and after a few k miles of use, the VI will have slightly higher viscosity, which is preferred.

Crystalworks, can you please document this procedure if not in pictures can you explain in detail what you changed and the part numbers. This may cure my problem.

This is the link to the Youtuber Crystalworks mentioned, states why he uses that Valvoline oil. There are many ads but worth hearing.

https://www.youtube.com/watch?v=vqQxnICNJxA

I have used the Maxlife fluid in several non-BMW cars and since my E53 didn't originally come with Dex VI, I decided to use the ML because it was economical and I THOUGHT it was slightly MORE viscous. It's actually very slightly LESS viscous than Dex VI. I don't know how it compares to the ZF fluid.

I don't know what to think about Nathan. I've watched several of his videos and appreciate him most of the time, but sometimes he'll make me cringe with his methods! He's got his opinions on stuff, like all of us, but I certainly wouldn't take his advice as gospel. Just my $0.02

AM.

Yep, from what I've researched, Dex VI is a superior fluid in just about every way. With an older transmission, it makes sense to me that a slightly more viscous fluid with the quality of Dex VI might make sense. I've read where some have used Mobil1's synthetic ATF that is noticeably thicker with good success. It's expensive, though!

For now, the MaxLife stuff is working fine and it definitely made it shift faster/cleaner vs. the old OE stuff I pulled out at about 125K miles.

AM.