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2001 Impreza RS
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Discussion Starter #1
yeah i'm about to change my rear diff. fluid and was thinking of using RL heavy shockproof gear oil, before i do i wanted to know if it is a good idea.
 

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'04 RS PBP w/ Black Tarmacs
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1,805 Posts
I wouldn't recommend it. If I were you I'd talk to the guys at Redline. They're pretty cool. Shockproof is for racing applications only according to them. Sometimes full on racing products aren't good for street cars. Like racing brake pads or straight weight oils for example.
 

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ok terrific.
'95 STi RA rep, rhd yo!
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5,195 Posts
I would recommend Royal Purple Max Gear 75w90. If you plan to use the Lightweight Shockproof in your car, use it as an additive, not a base.
 

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ok terrific.
'95 STi RA rep, rhd yo!
Joined
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5,195 Posts
I also don't agree with mixing oils either. It just seems like a bad idea to me.
Mixing oils isn't such a bad idea. One of the requirements, especially on syntethetic oil, is that it can be mixed with any other brand of oil. Mixing oils gives you some of the best additives from a variety of different companies.

Every heard of Scotty's Cocktail?
 

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wood grain grippin'
v2 STi wagon
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3,399 Posts
Uncle Scotty's Cocktail is full of FAIL

t3hWIT, have you seen that analysis has been done on NASIOC with the Cocktail? That ish EATS YO SYNCHROZ

I'll tell you what Wedge does. It's what I do. Redline 75W-90NS in the tranny. Redline 75W-90 in the rear differential. We both have mechanical rear LSDs, both autocross the shit out of our carz, and you know what? It rulz. The Slingshot was running over 300tq for a couple years before the gearset was changed, guess what the stock gears looked like at the time of upgrade? Mint.*

If you don't want to break yer trannyz, don't n00b-shift!

Brett

*That's what Wedge sez.
 

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ok terrific.
'95 STi RA rep, rhd yo!
Joined
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5,195 Posts
No Brett, I didn't see that. Care to post the link?

I've heard people swearing by it for years, but only recently have people been saying that it's not that good. A lot of people seem to be leaning towards a Motul combo recently.
 

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wood grain grippin'
v2 STi wagon
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3,399 Posts
Cocktail link: http://forums.nasioc.com/forums/showthread.php?t=920674&highlight=cocktail

someone decides to have the Cocktail analyzed: http://forums.nasioc.com/forums/showthread.php?t=1555876&highlight=cocktail

results in this thread, but it's really the above link you gotta read: http://forums.nasioc.com/forums/showthread.php?t=1489327&highlight=cocktail

All because people swear by it don't make it a good thing. There's a few reputable transmission builders on NASIOC who have also stated that the Cocktail is t3h FAIL for your transmission. Like I said, eatz yo synchr0z.

Brett
 

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2001 Impreza RS coupe
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mixing oils? what like having a diff oil in the trans than in the rear diff? cause i didnt put anything other than redline heavy weight gear oil in my rear diff and i did it because I read that it was a good product from people who had done the same - and its been working great so i dont see where youre going with this
 

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wood grain grippin'
v2 STi wagon
Joined
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3,399 Posts
mixing oils? what like having a diff oil in the trans than in the rear diff? cause i didnt put anything other than redline heavy weight gear oil in my rear diff and i did it because I read that it was a good product from people who had done the same - and its been working great so i dont see where youre going with this
your rear diff is connected to the tranny by the driveshaft and nothing more, the fluids don't mix. he's talking about mixing different fluids into the same case.

DvSkD4, how many times have you changed the fluid in your rear diff?

What I'm getting at is... it's just super freaking heavy. It's more weight than the gears need, so it's just fighting the low viscosity fluid in there. Not saying it's BAD for the diff, it's just not necessary and not really beneficial to performance

Brett
 

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2001 Impreza RS coupe
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your rear diff is connected to the tranny by the driveshaft and nothing more, the fluids don't mix. he's talking about mixing different fluids into the same case.

DvSkD4, how many times have you changed the fluid in your rear diff?

What I'm getting at is... it's just super freaking heavy. It's more weight than the gears need, so it's just fighting the low viscosity fluid in there. Not saying it's BAD for the diff, it's just not necessary and not really beneficial to performance

Brett
I have only changed it that one time, and yes it was EXTREMELY thick, so i see where youre coming from ... it is probably un-necessarily heavy duty
 

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ok terrific.
'95 STi RA rep, rhd yo!
Joined
·
5,195 Posts
Cocktail link: http://forums.nasioc.com/forums/showthread.php?t=920674&highlight=cocktail

someone decides to have the Cocktail analyzed: http://forums.nasioc.com/forums/showthread.php?t=1555876&highlight=cocktail

results in this thread, but it's really the above link you gotta read: http://forums.nasioc.com/forums/showthread.php?t=1489327&highlight=cocktail

All because people swear by it don't make it a good thing. There's a few reputable transmission builders on NASIOC who have also stated that the Cocktail is t3h FAIL for your transmission. Like I said, eatz yo synchr0z.

Brett
Thanks, I'll give it a read.
 

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Banned
'04 RS PBP w/ Black Tarmacs
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Mixing oils isn't such a bad idea. One of the requirements, especially on syntethetic oil, is that it can be mixed with any other brand of oil. Mixing oils gives you some of the best additives from a variety of different companies.

Every heard of Scotty's Cocktail?
Just because you could doesn't mean you should...

The best oils have the least amount of additives. In many cases additives make up for poorer quality bases. Additives also almost always have one thing in common. They do not lubricate. They are detergents and polymers and such used to stabilize the oil or make in behave certain ways under certain conditions.

Mixing oils makes it behave in a way the engineers haven't tested for. This might be beneficial or it could be damaging. I'd rather not take that chance.

I'm using what the manufacturer recommended. In my case I'm running Redline. 75W90NS in the tranny and 75W90 in the rear. It's worked great so far.

BTW thicker oils will rob HP. I understand modifying, but for the life of me I can't understand why people like to play chemist with their drivetrains.
 
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