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      04-03-2008, 02:12 PM   #2
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Part 2
Water and Fuel Hoses

Replace water and fuel hoses every 150,000 miles, highly recommended use of O.E. or O.E.M. hoses only, along with the original hose clamps or Wurth/Zebra replacements. The original BMW hose clamps are far superior to anything you’ll find in a U.S. auto store.

Power Steering Fluid

Replace every 30,000 miles. This is a very neglected operating fluid. Almost all BMWs use automatic transmission fluid in the power steering system, except for some E32 7 Series cars, which use Pentosin hydraulic oil. Nothing will balls up the works faster than using one when you should be using the other. Check the sticker on the reservoir, check the owner’s manual, and if you are still confused, take the car to a pro or e-mail me.

It is not necessary to evacuate the entire power steering system. I just open a line down by the pump.

I have had great experience using Red Line Synthetic Power Steering Fluid – 184,000 miles and counting on the original rack and pinion unit and pump on the vehicle I used to test this product. But I would not use it in place of Pentosin hydraulic oil where that product is specified.

Manual Gearbox Oil

Only synthetic oil should be used in BMW manual gearboxes, drain interval 30,000 miles

Red Line products are highly recommended ( Questions or problems, e-mail me or

All the BMW gearbox re-builders I know use Red Line MTL exclusively, regardless of model year or gearbox. The general consensus is, MTL is the better lubricant. However, the D4ATF product will require less shifter babying during cold operation. I use Red Line MTL in manual gearboxes except where I can’t trust the driver to shift properly when the gearbox is cold, in which case I use Red Line D4 ATF.

Automatic Transmission Fluid (ATF) and Filter

For older automatics using Red Line or other synthetic ATF, drain interval 30,000 miles. Old fashioned petroleum ATF, drain interval 15,000 miles

At various production dates in the mid-1990s, which vary according to model, BMW switched to their so-called “lifetime fill” ATF in automatic transmissions, as well as manual gearbox lubricant and differential oil. The reason for this, as far as anyone can tell, is marketing and not engineering – the idea being to foster the notion of the low-maintenance BMW.

There was no explanation of what “lifetime” meant, i.e., lifetime of the car, the component, or for that matter the driver. If it was the component, then obviously anything could be “lifetime fill”. The factory’s initial position is that these lubricants never need to be changed. Then, some time later, it came out that “lifetime” means 100,000 miles. Many dealerships are now recommending manual gearbox and differential oil changes be done at customer expense every 60,000 miles. Every independent BMW technician I know recommends a 30,000-mile interval, and many recommend Red Line synthetic oils (, but not for automatics with “lifetime fill.”

Older automatic transmission models, which do not have “lifetime fill” should have ATF and filter services every 15,000 miles if using petroleum ATF; every 30,000 miles with synthetic.

However, the modern automatic transmissions are different. No one knows exactly what BMW’s proprietary ATF is, so no one knows if there are viable alternatives. We do know that BMW dealerships charge about $500 for an ATF and filter service, due to the price of the ATF. And that’s assuming you can get them to do the job, which is not often the case.

Under no circumstances would I recommend draining any previously unmaintained automatic transmission with much more than 50,000 miles. I have seen it happen too many times, where a well-meaning owner or technician performs an ATF and filter service on a neglected but well-shifting automatic, and then all of the sudden it starts slipping. I can’t explain it, but my feeling is the fresh ATF flushes a bit of sludge from a place where it was doing no harm to a place where it does do harm. Overfilling, under-filling, and cleanliness are also issues in ATF and filter servicing, but these should not be problematic for a professional BMW technician, dealer or independent.

BMW has “backed off” their lifetime fill mantra for automatic transmissions, currently recommending an ATF and filter change every 100,000 miles.

My inclination is to tell people to change “lifetime” ATF and filter every 30,000 miles. However the fact is, I've seen BMW automatic transmissions that were maintained break anyway. In that event, say it happens at 90,000 miles, you would like to have that $1,500 you spent on ATF and filter changes to put toward your new automatic transmission. And if I told you to spend it on maintenance you’re probably not going to be very happy with me. On the other hand, I have seen maintained automatics last 200,000 miles. I have also seen unmaintained automatics last 200,000 miles, although both are very rare. There's just no predicting with these transmissions. When you choose to buy an automatic transmission, you also buy into the vagaries of the darn things, which is one reason technicians hate them.

Whether to maintain a modern BMW automatic is up to you. I am washing my hands of automatic transmissions – I don’t like them, I don’t buy them, and I don’t mess around with them under the car. At the end of the day, for long-term durability, order the car with a manual gearbox.

At automatic transmission replacement time, we are confronted with the reality that the local transmission shop cannot rebuild BMW automatic transmissions, even those built by GM (BMW’s GM transmissions bear not resemblance to GM transmission in domestic cars). There are some domestic specialists who concentrate in BMW automatic transmission rebuilding, and you’ll see their ads in Roundel. However, I have no experience with any of the current domestic re-builders. My experience in the past is…well, I wound up buying a BMW factory rebuilt automatic transmission every time, and this is the course I recommend to readers – “back to the dealer.”

Some of you, having seen the light, may be interested in converting to a manual gearbox. This is always possible, but for most of us it won’t be less expensive than a replacement automatic transmission. This is because of all the other parts and additional labor required. And the newer the car the harder the job will be. It is certainly a doable swap, but there’s no cost savings even if you do the work yourself. The exception would be if you have access to a manual gearbox donor car for little or no expense.

Differential Oil

Recommend Red Line 75W-90 synthetic gear oil, drain interval 30,000 miles in any BMW differential

Okay to use Red Line 75W-90 in place of BMW “lifetime fill” gear oil

Brake Fluid

Recommend one-year brake fluid changes, or prior to each driving school or track event. BMW now recommends two-year brake fluid changes, but used to recommend a one-year interval.

Recommend ATE SL brake fluid for normal street use, ATE Type 200 or Pentosin Racing Brake Fluid for track work or very high performance use


It has to be recognized that the benefits of good drive-train lubricant maintenance do not accrue until the car matures. The difference between the car that ran 15,000-mile oil change intervals and never had it's gearbox or differential oil changed (as per BMW instructions) and the one that ran high-end synthetic lubricants and had it's drive-line maintained in contravention of BMW's instructions, is the strong likelihood that the second car will be running strong at 200,000 miles whereas the first car will likely have a worn out drive-train. BMWs, and most modern cars, will run 100,000 miles just fine with zero maintenance.

So, if you're maintaining the car religiously only to sell it at 75,000 miles then you're a good guy for helping out subsequent owners. That's nice, but to realize the fruits of your diligence, you need to keep the car longer.

© 2002 Mike Miller