So as I get to know (and love) the 2008 MC Hatch that I got for my son, I'm looking at some of the maintenance items I want to do. Filters, plugs, etc are pretty straight forward. But I'd also normally fill and drain the tranny fluid just as a matter of course, so I know where all my maintenance is.

I've done some reading about auto tranny fluid on Mini's (similar to BMW's). Some say it's a "lifetime fill". Others say you should regularly drain and fill. And others say that if it's never been touched and you have higher mileage, you're best to just leave it be, as new fluid could open a pandoras box of problems. I also know that can't easily check the fluid level (a la dipstick) and that the drain plug has a filler tube that levels the fluid out, and draining it is about the only way to check the fluid condition.

So to you experienced folks out there - if you had 120k on an '08 hatch that was running well (upshifts and downshifts working as I'd expect, and no noises or slippage) - would you drain and fill (once, more than once) or just leave it be?

thanks for sharing your thoughts
andy

 

As you probably already know there is no such thing as lifetime fluid. Even when MINI uses the term lifetime no fluid change needed is really not a good idea. If it was me I would have it changed. But it is very critical that the correct amount of fluid is in the transmission when done. If not it will shift very erratic. This might be something you want to bring to a good transmission shop that knows these type of transmissions. With that kind of mileage im shocked the transmission shifts well. either your lucky or its had a service at some point. But lets just say your lucky and its the original ATF. I bet its very dirty and your on barrowed time! Im not one that would just leave it be because its working. I would have it changed! Maybe someone else will chime in and give you there thoughts. But you know mine Good luck!

 

Take it to the dealer or an "experienced" transmission shop that knows this transmission and what their doing. These transmissions need the correct type and amount of fluid to work properly. You can't just drain the fluid and put more in. You need to "measure" what you drain out and put the same amount back in. It's easier to pump the new fluid in and the dealer or transmission shop will have the right equipment to do this.

 

"Lifetime" usually refers to the lifetime of the tranny. It's a self-fulfilling prophesy - after tranny dies, you don't need to replace it's fluid anymore

The usual automatic fluid replacement interval on all modern cars is either 30K, 60K, or 100K. If you google around for tranny fluid change intervals on Aisin equipped cars (Toyotas, VWs, Saabs, Nissans, Volvos, GMs, etc), they all site different intervals, adding to the confusion. I changed mine, together with the filter, after 6 years and 55K miles. Mostly because that's when I got to it while the engine was out of the car (long story).

The old fluid was significantly darker than new, and the tranny started shifting smoother after the fluid change, especially down-shifts under load.

There is THAT school of thought, and the argument is that if you hadn't maintained your transmission for the first 100K miles, the fluid is known to be filthy. New fluid will only act as a detergent, and start washing contaminants from the places where they are not causing any trouble (yet), to where they might. If that's your concerns, and you intend to keep the car for a while, you can always change the fluid twice!

If you don't see any signs of leakage and the tranny is shifting fine, just assume that it's filled to spec!

If you plan on keeping the car past 200K miles, I would change the fluid and the filter. I did that on my car, though it was a lot easier for me as I was already swapping the engines (old N14 ate an exhaust valve on cyl 4) and the assembly was out of the car.

I used OEM fluid (bought from the dealer at ~$20/quart) and needed all 4 quarts. First 2.5 quarts came out when I removed the oil pan, another 1.0 quart after I removed the filter, and the final 0.5 quarts dripped out while I worked on swapping the engines for about 2 weeks. I had bolted the pan back on, then took it off one last time, and there was another half quart in the pan. I did install a new pan gasket, though the original looked good enough to go back on.

I measured exactly how much fluid came out to pour back the same amount. Easy with an extra lunch pan.

Total cost - $80 for the fluid + $45 for the gasket = $125 in parts. Labor for me was "while you are in there".
Not bad for a once every 6 years maintenance item!

If I wanted an "experienced" technician to work on my MINI, the last place I would look would be the dealer network. Those guys are half-competent at swapping parts under warranty, and that's about it.

FWIW - local dealers quoted between $650-$850 for the job when I inquired, a trustworthy independent wanted $550.

Dealers do sell OEM tranny fluid, per quart.

You can easily measure the fluid as it comes out.
And pour in the same amount back in.

Brain-dead simple. No equipment required, beyond an oil pan, and a funnel.

Hope this helps,
a