Should I change my transmission fluid?

[master4200]

My 2006 325i with an automatic transmission has 123,000 miles on it and I don't think the transmission fluid was ever changed. Should I change the transmission fluid or just leave it alone? will I have transmission problems if I change the fluid? The transmission is working fine with the rare jerk during gear changes.

[cochise325]

Yes change it. Right away.

You have a ZF transmission. So you will need 7 liters of ZF fluid. It is expensive stuff, but do not use anything else. You will also need a new transmission pan (which includes the filter element). Should also consider replacing the mechatronic sleeve while you have the pan off.

Search for the diy threads if you are going to do it yourself.

I have a 2006 325xi Wagon. My transmission fluid was changed at 50k, and again at 100k. I will do it again at 150k (I am at 138k miles at the moment).

Check parts prices at www.ecstuning.com

[master4200]

Thank you for the reply. So you don't think changing the fluid now will cause any issues? I heard it might cause gear slippage.

[sleeper bird]

I would say yes as well

[TonyAngel]

Well, the argument against changing the transmission fluid after so many miles is based on the theory that all of the friction material that has worn off of the plates is now suspended in the fluid and changing the fluid will remove the material and cause the transmission to slip. Personally, I'd change it. From what I've read, ZF trannies are pretty well built and problems with the hard parts are rare.

I recently changed my pan/filter and fluid for the first time at 90k miles. There was little stuck to the magnets (although I don't know what was trapped in the filter), but the fluid was rather thin. It isn't hard to do, but don't try to do it at a time when you will be rushed, just in case something goes wrong. For me, getting the fill plug loose (be sure to do this before draining the fluid) took a bit of doing and I broke a pan bolt due to torque wrench failure. Not big deals, but a bit time consuming to rectify.

Get you kit here...http://www.thectsc.com/products/oil-...ai-187-61.html

I only needed just shy of 6 liters. When you start working on that fill plug and you find that it is seized, DO NOT try to muscle it. I used a penetrant (WD-40 Specialty or PB Blaster) on the plug a bunch of times while tapping on the bolt to get it to soak in, then started the car, ran it to operating temp, then melted 3 ice cubes directly on the plug. After that, the plug broke loose with the use of a hex key with a box end wrench for leverage.

Changing the sealing sleeve is a bit more daunting, in that you could possibly bend pins when installing it and if you do this, you're going to have to straighten them or the car won't start. There isn't a lot of room to work either. If you have big hands, I'd suggest using 45* angle needle nose and some sort of "L" shaped tool for removal and installation. Just whatever you do, DON'T twist the sleeve while removing or installing. This is what can bend the pins. I knocked it out pretty quickly, but I sort of cheated. I used a fiber optic camera, taped in place, and used that to see what I was doing when installing the sleeve. Be sure to use vaseline to lubricate the o-rings on the new sleeve. It's a TIGHT fit.

[jno]

How do you guys feel about dynamic tranny flushing?
It seems far more effective at getting all the crap out.

[TonyAngel]

I think any sort of "flushing" is asking for trouble.

[cochise325]

If you like to flush your money down the drain, then go ahead and flush your tranny. Otherwise, practice drain and fill. And only use approved fluid, else you mix fluids from different manufacturers.

[sleeper bird]

Negative on flushing

[S197GT]

negative on flushing or drain/refill.

178k miles on our 06 330i auto and no issues at all; nothing done to transmission. my in-laws have a suburban with 250k miles on their transmission, many years pulling a 5k pound rv trailer, no transmission maintenance, they also have our 2000 cherokee we gave themm, 200k miles, no transmission maintenance. (cherokees are legend for their reliability though... and rust.)

now, having said that, if you can diy, sure! do it! if for no other reason than the fun of it.

otherwise, don't waste your time. what shops charge you for the service is outrageous anyway.

go to common issues or search the forum for how many people have transmissions failing on them and let me know what you find.

save your money for the replacement of leaking gaskets and diagnosing SES lights.

[cochise325]

Zf now recommends 60,000 mile intervals for changing the transmission fluids. You can do whatever you want with your car. It is your money. If you want it to last, and are not thrilled with the idea of spending $4,000 to replace it, you could pick up 7 liters of zf fluid, a $200 zf pan, and make her last.