How good IS BMW's 6 cylinder engine?

Ever try to eat a tape recorder? 8;)

-- Larry

Yes. Usually I just seethe quitely and alone... :-)

DAS

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And "quietly"...

DAS

For direct replies replace nospam with schmetterling

There are quite a few at my school that bind brain functions difficult!

Gosh - what an idea...........!

I've got a Nagra SN which you just about could. ;-)

Same here.

SHEESH!

In a manual box a human operates the clutch and importantly the gear level to choose what gear to drive in and do so in a coordinated manner.

In an automatic the gearbox selects and changes gear automatically according to the speed of the car. OK so the human has to decide whether to park, drive forwards, reverse or just rev the engine in neutral, but for normal driving a BW or GM 3 speed box would make a reasonable choice of gear automatically for journeyies lasting hundreds of miles.

A time switch is automatic,

usually

breathing is automatic.

Usually, but you can exert manual control - useful when swimming if you don't want lungs full of water.

Pre-selectors in the 30's IIRC

The ZF auto in the E90 is a phenomenal gearbox. It shifts silky smooth in auto mode and is appropriately aggressive in manual mode. It even rev matches (blips the throttle) on downshifts just like the SMG units. It's the closest thing you can get to a manual without tossing the torque converter, and I'd say it's appropriate for all but the most die-hard enthusiasts and track junkies.

The only downside to a BMW auto is that you're on the hook for all preventative maintenance from day 1 because BMW foolishly tries to sell customers on the idea of "lifetime" fluid and doesn't include any tranny service in their scheduled maintenance program. They simply expect you to replace the tranny when it blows up. The fluid and filter in the auto box MUST be changed every 30-40K -- regardless of what BMW or the dealer says -- if you want to get more than 125K miles out of it. Also, if you value the warranty you need to use the BMW-approved fluid. They can tell if you don't.

-Doug

I must disagree with you on the MUST or else at 30K as that could turn out to be once a year for some folk. My E38 on the old box covered 193k without any problems and I wouldn't say I nursed it as have many others.

My advice would be not MUST change the fluid but it might be ADVISABLE to CONSIDER swapping the fluid and filter but maybe around the 80K - 90K.

Have you got any proof of this? Plenty say engine oil *must* be changed at

3000 miles. But they're wrong too.

Oils can be analysed for their condition. You'd need to do several transmissions at 40k miles and find evidence of that ATF deteriorating to be certain it needs changing. Otherwise stick to the maker's recommendation of about 80,000. The ATF specified is expensive.

As you say Dave and to add to my view - 30K can be a year of driving for some folk and if this is a MUST I don't see or hear of many replacement auto boxes being fitted under warranty by BMW dealers between 30K and the 100K warranty period over 3 years.

Change engine oil @ first 500 miles and then every 3000 was 1960 stuff then came the 5000 mile service interval from Ford of Briton on the old V6 Zodiac and the

1600 Cortina. Now it appears that the idiot light is back for all and dictates are a thing of the past like oil pressure gauges, volt meters, ammeters etc. How long before the speedo and rev counter go in their present format and we have to rely on sat-nav reading for speed and distance and both being relayed back to base so the Police can summons us without giving us the legal warning.

Ho Hmm! Where's me bike?

Ford of Britain

I think what is confusing is that the OLD BMW service routine called for changing auto tranny fluids every 30K miles. So if your car is from the 90s or earlier, that is probably a good routine. However, for newer BMWs, I believe the recommendation is every 80K or 100K. The difference is the type of fluid used. The older BMW fluid used standard fluids like Dexron II or III. The newer stuff is synthetic and designed to last longer. In a way, its similar to engine oil. Older cars ran on dino oil and recommended changing intervals ranged from 3K to 5K miles. In contrast, newer BMWs use synthetic and recommended intervals is from 7K to 15K.

Manual tranny fluids can still be changed every 30K miles with a good synthetic. Its easy, so why not?

If you can, it is still recommended to change differential fluid every 30K. Us a good synthetic from Redline or RP, but its my understanding that some of the newer BMWs don't have a drain plug in the differential. Still, there are ways of suctioning out the old fluid.

But unfortunately not all the shit however, the old trick of sticking a big magnet to the inside of the sump pan on the tranny or even drilling and tapping the diff for a drain plug if one is that paranoid will work.

It was not my intent to start up an ATF debate. That's been done to hell and back here and in other online forums. However, I'll respond and clarify my comments.

I'll agree that a more realistic engine oil change interval is 5000-7500 miles. But while an oil analysis will reveal some anti-wear additive (molybdenum, typically) remaining at 15K miles, oil that age has long ago lost its ability to hold contaminants in suspension. When the oil can't hold any more dirt, it winds up deposited elsewhere in the form of sludge. An engine can tolerate a huge amount of sludge, but a transmission cannot, so suggesting a filter and fluid change at 30K mile intervals is quite reasonable.

As for the cost of the fluid, the earlier non-steptronic GM trannys (a la E36) use standard DIII fluid and you can source that for $2/q at Walmart. The oil for the ZF transmission is another matter, however. It can be sourced directly from BMW at $20/l, or from VW at $11/l, or from select aftermarket vendors that explicitly specify compatibility with the spec for around $8/q. It's not that bad if you know where to look.

Yes, but a significant number of these boxes are being replaced between 100 and 125K due to a lack of maintenance before 100K. And that's because everyone listens to the BMW money-making-machine and changes the oil too late in the wear cycle if they change it at all. The result of a change that late in the game is usually more harm than good because the detergents in the new oil free those deposits and clog the valve body or just interfere with proper meshing of the clutch plates.

So I'll clarify my statement. If the OP intends to keep the car long term (> 4 years or 60K miles) AND he wants to prolong the life of the transmission through regular preventative maintenance, he MUST conduct the first service at 30-40K miles and conduct additional service at 40K mile intervals thereafter. If you start maintaining the transmission at

80K or 100K miles as BMW recommends, you've already lost the battle.

For further reading:

?t=175161?t=498651

-Doug

Sludge comes from the byproducts of combustion which get into the oil via the crankcase. This is why good crankcase ventilation is important - if the breathers get blocked you'll soon get sludge forming.

If there's combustion going on inside your transmission a fluid change won't help. ;-)

Ah, sludge. It's one of those "technical terms", which refers to any generic dark colored "gook" (how's that for defining one technical term with another) that forms as a result of either combustion byproducts or wear of frictional materials in a closed system.

Rest assured, transmissions (particularly those with a zillion clutch packs like the ZF steptronics) have a problem with sludge or gook forming in them over time if you don't change the oil often enough.

Love to continue the debate, but Entourage is coming on HBO soon and I have to prepare the onion dip. :-)

-Doug

In my experience of fixing many autos 'sludge' only happens after the transmission has started to fail. If the amount of debris caused by normal wear was a problem they'd fit a proper filter rather than just the gauze one to protect the pump from foreign objects. I recently stripped a transmission where a gear train failure had occurred and the fluid was not showing any signs of friction material contamination despite being due for a change. If on draining down the fluid looks contaminated the transmission is not long for this world. Of course I'm not saying that fluid doesn't need changing due to other factors - it will deteriorate in other ways. But changing *long life* fluid at 'normal' intervals simply wastes money and serves no purpose.

THREE-speed. How outmoded is that?

More to the point, how inefficient at high speeds is that?

DAS

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