PeterK

I'd like to change my transmission fluid to Redline as a proactive measure and can't find the spec. I know it takes 2.1 qts but what weight oil? Redline MTL is 75W80, MT-90 is 75W90. Which is correct per manufacture's specifications?

PeterK

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PeterK

... do transmissions have to &quot;break-in&quot; before switching to synthetics? nt

mne

due to meshing of gears vs. seating of rings in the cylinders. A transmission would be ok to start out with a synthetic and run it forever. An engine requires the rings to 'mate' within their respective cylinders for proper compression and oil control, therefore a petroleum is better initially... then later switching. The jurys still out on what the 'optimum' time is before the switch. It's very much a 'personal' call. I'm going to do it at 5k. Line up 10 people and you're likely to get 10 different answers on this one.<br>

PeterK

Thanks for the info - <p>Some have said it takes 8-9k before the rings are "optimally" seated to prevent the oil wiper from leaking later on but, I'm with you and will change at 5K service. I will also pay to get an interim non-synthetic oil change before the 5K interval. At 5K, I'll probably use Mobil1 tri-synthetic (vs. dealer stocked Syntec) since Redline and Amsoil, and Neosynthetic are all $8-10/quart and Mobil1 is just $4 but for twice a year (at most), I may spend the extra bucks for Redline since it's not that much $$.<p>Any idea as to what weight tranny fluid to use? I saw that you picked up the Mobil1 for yours but since I have more time (no grind), I thought that I would at least try to get the Audi "correct" weight.

mne

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ChuckH

All VW/Audi transmissions I've know used the 75W-90, including my 90Q. However, the Redline MT-90 made my 90Q almost completely unshiftable when the temperature got below about 40 degrees, and it took a long time to warm up. It is the only 75W-90 gear oil that made my shifting impossible, and I've tried 5 or 6 different brands. In my case, Valvoline seemed to work pretty well, but now I have the MTL in there. My independant said it would be fine and he recommended it. mne used Mobil 1 in his TT. Having used Mobil 1 engine oil for many years and based on mne's results, I would say that's probably your best bet for the 75W-90 gear oil. HTH!<p>Charles<br>