[GoRomeo]

Hi guys,

I ve read some stuff on AT trannys on e90s but not sure if there is a preventive maintenance I should follow when it comes to my tranny. I am at 90k miles and would like to know if changing my fluid/filter its a good idea? Or leave it since is a "lifetime" fuild. Even though i dont have issues I would like to know if its a easy process or not. Salud!

Thanks

[project6]

Change it. "Lifetime" only means in the lifetime of the warranty or the lifetime of the fluid.

Check the DIY section. It is relatively straight forward, depending on your mechanical inclination.

[GoRomeo]

Originally Posted by project6

Change it. "Lifetime" only means in the lifetime of the warranty or the lifetime of the fluid.

Check the DIY section. It is relatively straight forward, depending on your mechanical inclination.

Thank you Sir! I will add it to my list of things I need to do on my car before summer ends.

[bumere90]

Change it every 30k-50k

[GoRomeo]

Originally Posted by bumere90

Change it every 30k-50k

Really? man It definately needs to be changed then. Do you feel any difference after you change it like smoother shifting etc...? Thanks

[E90Company]

Originally Posted by GoRomeo

Really? man It definately needs to be changed then. Do you feel any difference after you change it like smoother shifting etc...? Thanks

I had my 6 series's tranny fluid replaced at 33k, and it was alot smoother. Can't tell you for the E90, but I would assume it's the same deal.

[Brad from the OC]

"Lifetime" can also probably include your life also. Once you are gone, I doubt if anyone will remember the last time the AT fluid was changed.

[jphughan]

Mike Miller's Old School BMW Maintenance Schedule recommends 60K, I believe. He goes into more detail about transmission fluid flushes in particular, specifically that if you've got a high-mileage car and have NEVER changed the fluid, it can occasionally do more harm than good, but at 90K I think it'd still be a good idea. Every 30K seems a bit much IMHO.

[gatoman39]

Somewhere around the 40-60k mark, you can time it with the spark plug change if you wanna kill 2 birds with 1 stone.

[bumere90]

Originally Posted by jphughan

Mike Miller's Old School BMW Maintenance Schedule recommends 60K, I believe. He goes into more detail about transmission fluid flushes in particular, specifically that if you've got a high-mileage car and have NEVER changed the fluid, it can occasionally do more harm than good, but at 90K I think it'd still be a good idea. Every 30K seems a bit much IMHO.

it won't do any harm if you do it properly
you don't have to drain the entire fluid, drain first half, replace it with a new fluid, drive it for some time then repeat the process.
when you completely drain the trans fluid and introduce fresh fluid that is when the problem occurs.

[project6]

Originally Posted by bumere90

it won't do any harm if you do it properly
you don't have to drain the entire fluid, drain first half, replace it with a new fluid, drive it for some time then repeat the process.
when you completely drain the trans fluid and introduce fresh fluid that is when the problem occurs.

What is the principle behind the "drain half" and what kind of potential problems are we looking at?

[jphughan]

Originally Posted by project6

What is the principle behind the "drain half" and what kind of potential problems are we looking at?

You should read Mike Miller's guide, by basically his THEORY to account for long overdue changes causing new problems is that sometimes flushing a bunch of old fluid all at once and then introducing new fluid can dislodge some piece of gunk from a place where it wasn't doing any harm to a place where it is -- gunk that wouldn't have built up at all had the fluid been changed earlier. He admits he has no proof of this, but it makes sense to me, and flushing half I suppose would reduce that risk. That's clever.

[GoRomeo]

Originally Posted by jphughan

You should read Mike Miller's guide, by basically his THEORY to account for long overdue changes causing new problems is that sometimes flushing a bunch of old fluid all at once and then introducing new fluid can dislodge some piece of gunk from a place where it wasn't doing any harm to a place where it is -- gunk that wouldn't have built up at all had the fluid been changed earlier. He admits he has no proof of this, but it makes sense to me, and flushing half I suppose would reduce that risk. That's clever.

Thank you all for your opinions. I will keep you all posted. Happy Friday!

[EQUANT]

I personally sent an email to ZF and they replied that the oil should be changed at 80-120,000km (for my tranny), depending on the way the car's been used.

[chris95559]

:threadjacke d:

[Saintor]

I won't touch it up the time I will get rid of my car at 185000km.

[mike-y]

changed mine right at 100k miles (ZF trans). the fluid still looked good actually (not black at all, fairly transparent), and there wasn't any material on the magnets. changed the pan also, since it has a built in strainer. can't say I really felt a difference afterward, but the car seems to run a bit better, but it could be just placebo.

I definitely feel a lot better now that it's done though.

[Martin328i]

I am going to do mine at 100,000 miles, too. My indy shop said the old school schedule is outdated with the advances in synthetics and additives. I do my oil with synthetic every 7500 miles.

[Blubaron79]

My SA said if you have the extended maint. plan they change it at 100k miles.

[Bobble]

Lifetime means the expected life by the manufacturer which is ZF. It's 100K and change it, unless you track the car(with an auto???) changing ahead of time is a placebo effect. I've had 3 previous BMW's all went well over 175K before I got rid of them and I adhered to maintenance plans exactly on everythng except oil, I did that every 7500. 30K is a bit overzealous but it's your money and time. Also not a hard DYI and I do my own maintenance on all my cars once out of warranty.

[Surly73]

On E39 transmissions (ZF and GM) the change can be dramatic. IMO 100k is too long.

The filter should be changed at least once at a reasonable interval to get rid of all of the break-in wear material. After that, you could change the filter every 2-3 fluid drain/fills.

If you adopt a shorter interval (like 30-50k miles) it's a much easier DIY and you can afford to do a drain/refill (which doesn't remove all of the fluid) instead of doing a maximum interval and having to go to every measure possible to extract ALL of the old fluid.

On average, changing half of the fluid 2-3x as often results in very good condition fluid in the transmission all of the time. You also get an opportunity to look for abnormal smells, leaks, low fluid levels etc...

Of course, I believe heavily in preventive maintenance. On the other hand, my vehicles have rewarded me handsomely for that.

[x26]

Originally Posted by Brad from the OC

"Lifetime" can also probably include your life also. Once you are gone, I doubt if anyone will remember the last time the AT fluid was changed.