My 94 840i has 208,000 kms on it. I want to change out fluids (I know this was never done before I got the vehicle),but a buddy said that it would be bad juju to change the tranny fluid now. Does this sound right? The car shifts "Ok", but I know it could be better. Any advice would be greatly appreciated

its a tricky subject dude, i personally would change. Make sure you get the right filter and fluid, also check on the e38 forum on this site as i have seen a detailed thread on how to change the fluid. Its a special Esso fluid.

I would change only some of the fluid and replace the filter to be on the safe side. If the old fluid is extremely dirty then new fluid could possibly dislodge greesy build ups within the oil galleries which could cause blockages.

However many have chaged successfuly its not a real issue all depends on the general condition of gearbox.

I have about 94k on my 328i and have not had an oil change and the box shifts lovely with no slipage or play!

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thats about 130k miles. It should be oke to change but many people would say to not change the oil at this point. Many people say the auto tranny will be dead around 120-160k mile range anyway. Their theory is that if you got that many miles out of it then it will last an another 10-20k miles and then you will rebuild it anyway.
I trust the BMW transmission even though the statistics say they are not the strongest ones. I would change the fluid and filter - approx. $200-260 in parts or so due to the high cost of the oil. Before you order any oil, take a look at the oil pan - it is marked which oil do you need to use.

I don' think you will hurt the tranny but again, you might just leave it as it is.

Good Morning

The ZF transmissions used in BMWs are one of the strongest and some go way over 200k miles, however this is mainly due to how the car has been driven.

Like Laszlo said, its best to check which oil the transmissions uses via the label.

Good Luck

Thanks to all for the advice, I'm gonna tread lightly as it's not a problem at present. How much does it usually cost to rebuild the tranny? I've seen kits for sale...

Kurt Koeller rebuilds them for around $1600-$1700, and he is an authorized ZF Transmission God.
He is located in Michigan though, but usually they can be rebuilt in about a day. The majority of the time is going to be the shipping back and forth (well worth the effort). I am sure there are some folks over in Europe that can do the same thing.

Hopefully I don't get killed with the euro rate. Thanks.

If your shipping from Italy to the States the dollar rate will be in your favor.

Hi, if you are still thinking about changing your trans filter.....TxGR8White is correct about Kurt. He helped me with changing my 740i with a filter kit and the location to get the Esso oil (it was from a VW dealer but had the same number as for BMW but much cheaper). It's an easy job if your able to get under the car okay.
Good luck,
P. Ford

last weekend, same engine and trans as yours. I have 177,000 MILES on mine. The fluid was black and nasty. I also re-built the vale body with the ZF kit. It shifts like new, and I'm sure the new oil is nothing but a benefit.

Its not that hard a job, just very messy, since you have to fill it from the bottom (more fine German engineering...:shifty).

Just don't do a "flush"! Only replace the fluid tht rains out natrally, replace the filter, and if you feel up to it, do the valve body kit since it has the ceck-ball upgrade.

Regards,
M.R.

Thanks for the info, wish me luck...

Whats the big deal about changing transmission fluid?

kind of like changing your underwear - it may be okay for a while, but at some point you will be getting uncomfortable and it might affect your walk - same thing with the transmission fluid, motor oil, etc...

Indeed, this is very true.

Even at 62k, I worry about changing it but it will need to happen sooner than later. I will wait until 75k. Differential will be done at the same time. Makes sense. What would make better sense is popping in a 3.15 LSD :D

sure you wouldn't want a 3.91? it is a quicker rear end.

I've thought about a 3.91, but I wonder how high it would rev at 70-80mph fwy speeds. Wouldn't it rev real high?

Maybe a dumb question ... But... What happens with the top speed limiter when you swap out the gear ratio? Where is the speed "sensed" from?

The speed sensor reads the rotation of the axle so changing gear ratio doesn't affect the speed signal.

Through very loose translation, a BMW mechanic over hear basically said the same thing as M.Rad. As long as I don't "flush" the engine, I should be good. Still working on my front suspension, so that will probably be one of the last things I do, besides changing the oil and any other filters I find. Ciao!!!