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      07-18-2010, 06:54 PM   #9
wolfe
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Drives: e82 / e70 / r56 / r60
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Quote:
Originally Posted by JimD View Post
Great article! Pictures are very helpful. I've always used MTL in manual transmissions, however. I checked the Red Line website and they recommend D4ATF for newer bimmers but it doesn't seem right to me. Can you say how long you've had D4ATF in other bimmers?

Jim
I was also a bit hesitant about using ATF in a manual transmission. Here's my anecdotal reasoning on why I went for it. Naturally, this is just my opinion based on my own limited experience:

Prior to the 128i, I had an e46 330i 6-speed. I bought that car certified preowned with 37k miles on it, and the transmission was a little crunchy from first to second, especially when cold. I replaced the transmission fluid with redline MTL, and immediately noticed an improvement. But, as soon as it turned cooler (and I'm not talking cold either, I'm in FL) again the shifter was crunchy, moreso when the car was cold. It became next to impossible to shift into first from a stop without a crunch, and the shifter required considerable pressure to push into gear. By no means was I slamming through the gears, and I always take care to shift more gently until everything's up to temperature.

I replaced the MTL fluid several times at very short intervals until the fluid came out perfectly clean (100, 200, 500 miles) on the advice of a very reputable BMW transmission rebuilder - he suggested I try this as a last resort before considering a rebuild. It didn't really help, sadly.

Then last winter, I had the car at an independent mechanic for some other work, and mentioned the poor shifting. The MTL was replaced with a quality ATF (didn't say which kind, may have even been D6), telling me that several other customers including one very picky guy had loved the change it provided. Sure enough, the improvement was massive. I had run MTL from about 40k miles to 58k, and then had the ATF from 58k to 70k which was when I sold the car. The ATF gave a consistent shifter feel the entire time, through winter and summer.

I also asked redline about this new car and what they'd recommend, and they told me D4 ATF.

This next part isn't something I'd put much weight behind, because it's impossible to say this for sure without any scientific testing. However, I feel that on my 128i since changing the factory fill BMW MTF LT-3 fluid out with the redline D4 ATF, again the shifter requires marginally more pressure to get into gear but it does so very smoothly. I paid very close attention to the shift feel right before I changed the fluid, and a very slight 'texture' was detectable through the shifter when shifting. By no means would I call it a crunch, but along the same lines only much, much less pronounced. Now the shifter just slots into any gear with a solid 'thunk', with no perceptable 'texture'.

I plan to keep a close eye on it over the next few thousand miles, and if I notice anything out of the ordinary I'll change the fluid back to MTF LT-3. In fact, I'll probably drain this out at around 10k miles to see how the fluid looks in terms of wear particles, then decide what to refill it with.

Based on how the transmission, diff, and engine oils looked after only 1200 miles, I'd suspect that changing the fluid is maybe more important than what it's changed with (within reason).

Last edited by wolfe; 07-18-2010 at 07:10 PM..
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