overfilling MT oil?

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206er
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overfilling MT oil?

Post by 206er »

on certain transmissions it is common practice to overfill the oil slightly. does anyone do this on their 5mt and by how much? how many quarts exactly? I cant think of any real negative effects of this, but I could be wrong. comments?
1994 Touring Wagon: ruby mica, 5mt swapped
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vrg3
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Post by vrg3 »

I would imagine that if you overfill the transmission enough you could get oil frothing, which would reduce the oil's ability to form a film between parts, resulting in potentially damaging metal-to-metal contact.

Why not just fill it to the correct level?
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
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206er
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Post by 206er »

I heard somewhere that it can keep the gears lubed a little better. it may not be applicable on a 5mt, but some trannies have oiling problems. something about helping 3rd gear.
1994 Touring Wagon: ruby mica, 5mt swapped
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0perose
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Post by 0perose »

seems like this would put extra stress on seals and stuff
yo mang, can I get a rootshell?

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entirelyturbo
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Post by entirelyturbo »

0perose wrote:seems like this would put extra stress on seals and stuff
That's what I would think, and it's no picnic replacing seals on Subaru MT's...
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vrg3
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Post by vrg3 »

206er - Hmm, so you're wondering about the possibility that FHI engineers decided to make the specified capacity lower than would be ideal for lubrication. The only reason I could imagine for anyone doing that would be that maybe less oil would mean less drag as the gears spin through the oil.

I doubt that's the case, though. For one, it seems like the reduced lubrication would cause more friction anyway. And for another, I would just have a hard time believing that FHI would have done something like that to us.
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skid542
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Post by skid542 »

^^^ Agreed. Any engineer that would decide to have added friction over a slight loss of power in the driveline for a market car is an idiot. Perhaps somewhere out there are old transmissions that do better between two particular gears when they have more than specified oil but it's certainly not ours :).
Lee

93' SS, 5mt swapped, 182k, not stock...
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206er
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Post by 206er »

turns out the guy I heard it from was referring to a SM-465 which Im sure is not designed as well as a 5mt. I'll just be filling up to the correct amount with good ol dino oil then if I decide I need to I'll switch to something like redline or royal purple.
1994 Touring Wagon: ruby mica, 5mt swapped
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