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Experimenting with Wally World supertech 75w-90


RobY

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you have a GT with rear LSD? i thought it is to be used only for top off? i figure it doesn't have the correct additives for LSD?

 

The GT has a viscous rear LSD.

Yours has an open diff.

 

In both cases, the gear oil itself does not affect the lockup behavior of the differential. Clutch type diffs are picky about their oil.

You can run any GL-5 75w90 gear oil. I ran Redline 75w90 in my rear diff with good results. A more slippery gear oil in the rear diff will reduce operating temps.

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No... the LGT has an OPEN front diff... a VISCOUS center diff... and a LIMITED SLIP rear diff.

 

FYI: Viscous [coupling] is a type of limited slip differential. As are helical gear, clutch type, and electromagnetic. The STI has a gear type (Torsen) rear diff, ours is viscous coupling.

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spec b has rear torsen to i believe.

 

as for refilling the rear LSD with this supertech stuff, i now believe its fine, because the viscous diffs are sealed units correct? you only need the fluids with friction modifiers if its a clutch type diff.

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as for refilling the rear LSD with this supertech stuff, i now believe its fine, because the viscous diffs are sealed units correct? you only need the fluids with friction modifiers if its a clutch type diff.

That's correct. The viscous diff's are sealed.

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FYI: Viscous [coupling] is a type of limited slip differential. As are helical gear, clutch type, and electromagnetic. The STI has a gear type (Torsen) rear diff, ours is viscous coupling.

 

 

Nope. LGT rear differentials are clutch type... not viscous.

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  • 1 year later...
  • 3 weeks later...

Glad this thread was bumped. Put some in and shifting has been great.

 

I've used uncle scotty cocktail, redline, subaru extra S, castrol, and this fluid is by far the best so far. Time will tell though.

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Glad this thread was bumped. Put some in and shifting has been great.

 

I've used uncle scotty cocktail, redline, subaru extra S, castrol, and this fluid is by far the best so far. Time will tell though.

 

so you feel supertech is better than extra S?

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Well yes and I dunno..

 

It is shifting much, much better than any other fluid I have tried. I am maybe a little too picky, but the supertech stuff shifts by far the best.

 

As far as if it is "better" than the Extra S I don't have any lab analysis of either stuff as a virgin sample. I also don't have any uoa of both fluids of similar mileage and driving conditions. So without this I can't really say that it is "better".

 

I have only put a few hundred miles on the stuff so far but again I have tried just about every gear oil out there. Suprisingly this stuff has been the best. I am really happy with it.

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  • 5 years later...

Going to bump this up. Used this in my '11 Legacy 6mt in gear box and rear diff. Already a considerable amount of improvement.

 

Now, car has just a hair under 116k, last recorded time the gearbox oil was done was at 54k, rear diff I don't think has ever been done. So I really can't say how great it is, other than my shifts are now literally buttery smooth.

 

I will update if I have any problems within the next 30k miles!

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  • 4 months later...
Just bringing some life to an old thread! I've been running Supertech SynBlend 75w-90 up front and Full Synthetic 75w-90 in the rear diff. Great stuff at a steal of a price. I know it's probably overkill but at less than 20 for 4 quarts I simply replace it every summer.
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  • 8 months later...
I am running Subaru's 75W90 High Performance Gear Oil and it sucks after 6 months of driving. I am seriously going trying this out.

 

I'm over 1 year and 11,000 miles in on it, still feels just as buttery as it did on day 1. Even on brutal cold days we had this past winter. Try it!! If you aren't satisfied, drain and replace, and at the very least you did a solid flush for like $30.

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