Originally Posted By: BoleCailey
Anything wrong with having it whine? I can overlook it as long as its not hurting the differential.
Possibly. It depends. If the whine is coming from the fluid shearing or the friction modifiers breaking down somehow, then that could have very bad implications in the long term.
Originally Posted By: BoleCailey
If there is nothing wrong with it, I will just run Motul or some other high end 75w140.
That should be fine as long as you either make sure it has friction modifiers for a limited-slip differential already mixed in, or buy the friction modifier separately and mix it in yourself.
Motul Gear Comp FF might do well for you.
Originally Posted By: BoleCailey
People on the mforum's seem way to anal about running OEM fluids. They bash the [censored] out of redlines motor oil, and I know it is good stuff from what I have read on here.
Yes, they do get out of hand sometimes. I think the Red Line thing is kind of overblown because a few people used the wrong fluid (which happened to be from Red Line) in their transmissions and had issues.
However, it's always worth remembering that your car (unlike, say, mine) is not just a hopped-up 3-series, nor is it simply a pick-and-mix of "better" parts from the BMW parts bin. It is comprehensively engineered and a LOT more highly developed. BMW took a lot of time to get a lot of things exactly right. Aftermarket substitutes are a gamble that most owners are quite understandably unwilling to take, and most of them -- not all, but most -- tend to be worse than OEM.
As a quick aside, the above is especially true of the engine oil: Castrol TWS was developed by Castrol and BMW specifically for BMW M engines, including yours, and is a derivative of one of the best and most successful lubricants ever made. How can anyone beat that, let alone a small company like Red Line -- let alone in a product that they are offering at a lower price, despite much lower economies of scale?
So, yes, they take it too far on the forums, and most people don't have the info to back up what they're saying. However, there definitely are reasons to stick with OEM for this car, at least for most things.
That's the catch with the E46 M3: it's the only car for remotely the same price that does everything so well, but it offers less latitude than its competitors in terms of operating and maintaining it. Porsches, Mercedes AMG cars, and some Audis come relatively close to the M3's capabilities, while letting you run lubricants that you can quite easily cross-shop and buy from a wide variety of stores. Food for thought.
