I looked at the link you provided from the audi forum, and one guy had a problem, apparently his seals leaked which he claims was from using the MTL oil in his audi. Other folks posted replies that they have had no problems with redline Also that thread is eight years old. These trannies are tough, you could probably run butter in them for the short 36K miles that the warranty covers. (Note: Do not run replace your gear oil with butter) I wouldn't worry about voiding the warranty, but I would like mine to last as long as possible. For what it's worth, my 2003 Vibe Owner's Manual says in the Recommended Fluids section on page 7-44:quote:Manual Transaxle: GM Goodwrench Synthetic Manual Transmission Fluid (GM Part No. U.S. 12346190, in Canada 10953477 - 1 quart) or SAE 75W-90 GL-5 gear oil.I haven't changed the oil in mine yet, but when I do I will go with a 75W90, probably a synthetic since that's all I hear here on genvibe. Maybe that 12346190 is already in there from the factory and if it's the best stuff in the world, then I won't bother changing it. It would be nice to know what's in there on a new Vibe, but if it was the 12346190, that wouldn't explain the improvements you felt when you had 12346190 put back in.I wonder what the recommended fluid is for the same transmission when it's installed in a MAtrix? Toyota transmission, I'd trust them to know better than GM what oil to use in it.Interesting comment on one of the posts in that thread you referenced, shows up at
http://www.audifans.com/archives/1995/08/msg00493.html, where "tom" saysquote:I've been using Amsoil Gear Lube (75-90W) in various transaxles for years and have never had any problems, in street,race, or rally cars. Try it, you'll like. (but you'll probably hate the dealer.)I wonder what Derek (Admin II) would have to say about that last comment?