porsche911targa

Today, I was having a casual conversation with the shop foreman at my dealer and I mentioned that in April I'm going to ask them to replace my tranny fluid and filter, since I'll be due for other service.

To my surprise, he was very adamant against doing this. He went on to explain that the fluid has lots of detergent and is under high pressure. He then said that with time, internal gearing gets "a little loose" and the tranny compensates by using a little less pressure. When the fluid is changed, he said, the pressure goes back up and the risk is that the 'looser gears' could cause trouble.

Now, as many of you know, I had the tranny replaced under warranty at 38K miles. With the car now at 68K miles, I figured that 30K would be a safe interval to replace the fluid and filter. I plan to keep the car six more years. I estimate I'll be putting in another 60~80K miles before getting rid of the car.

The thing that scared me was that he said that if I choose to replace the fluid and then something goes wrong, BMW will not take responsibility for anything that goes wrong, whether the car is still under CPO warranty or not. He said they'll do the work, if I insist, but I should be aware of this.

What are your collective thoughts on this? Will BMW really void my warranty for replacing the fluid at one of their own dealers? Would you go ahead and replace the fluid anyway? He said the same thing will happen with the Power steering fluid, since it's under even more pressure.

Please

healthservices

speedbagger

if there's no issue, i wouldn't touch it--ever. its not a manual. just make sure its not low.

jay bimma

the only way for the transmission to increase pressure if this is even true would be to reset a computer or module...by simply draining and refilling the fluid and replacing the pan & gasket, the car has no idea that you are even doing this. many people has put new tranny fluid in their car including myself. i have replaced every fluid in my car (tranny, front/rear diff, transfer case, p/s, brake, coolant and obviously engine oil). haven't ran into any problems yet. fluid changes will never hurt a car unless you wait too long past the interval (i.e. tranny fluid). if your only planning on keeping the car for another 60-80k then i wouldn't waste my money on the service unless you hope to recoup that as a selling point! and yes, they can void your warranty on your transmission by changing the fluid if it is changed before the warranty expires since the transmission fluid is so called "lifetime". but if you change the fluid by yourself or by a independant mechanic with OEM/BMW fluid...the dealer will never know the difference in fluid since yours is not burnt or overdue. i changed my tranny fluid at 60k and the old fluid looked just as good as the new fluid (maybe just a bit darker but nothing crazy).

AchtungE60

When you do a drain/fill via ZF recommendations, you are starting the tranny with only half the fluid in it and then filling to correct amounts at correct temps. So yes, the tranny does know you're doing something.

OP - I changed mine (See DIY here) @ 98K miles. I WOULD NOT TRUST AN INDEPENDENT TO FLUSH....NO WAY

PaoChe

Everything anyone has ever told me has always been along the lines of, if you don't do it by about 60k miles don't bother, fresh fluid in an older transmission equals more slip in the older transmission from the fresh fluid.

example: My dad never changed the transmission fluid in his E39 and it's got about 200k miles on it now so I don't see any merit to changing the fluid.

xcntrk

How did your original fluid drained compare to the new? Were there clear signs of breakdown or discoloration?

DavidF

People will debate the pros and cons of auto box fluid change till the end of time. I am in the camp of replace the fluid every 80k miles. No fluid is going to last a lifetime, unless you believe the "lifetime" is the period of time it takes the old and dirty fluid to kill the transmission.

Bottom line is that the fluid picks up wear particles from the transmission and the viscosity and ability of the fluid to do it jobs changes. Some say new fluid will cause debris to dislodge and make the tranny fail. Hogwash...there should not be any debris in the transmission to dislodge. It may clean it up a bit, but that is a good thing.

Many poeple are having good results using BG flushing services. But, if you do it yourself, you are only changin a fraction of the fluid each time...so do it more often and you are good to go.

Just do it, nothing bad will happen unless the tech screws up the process.

Bad Debt

I had mine changed with my failing mechatronics unit. I would have had it changed either way at around 45,000 miles. I agree, nothing is lifetime, unless lifetime means 100,000 miles. Also it seems like people are using the terms drain and flush interchangeably, when they are quite different. High mileage, I would only do a drain so that I wouldn?t loosen particulates and create problems.

sachal007

i have 38K on my car? I was planning on replacing the tranny fluid, brake fluid and diff fluid
around 50K. Should i or not?