Manual Transmission Oil 2008 Impreza

[zubricki]

Hi All,

 

I noticed a spot on the driveway the other day and, when I finally got a chance to check it out this weekend, found out it was coming from the transmission.  Best I can tell, it seems to only be leaking from the main drain plug.  Not exactly sure why that might've come loose, but I don't see any fluid in uphill from the plug so I'm crossing my fingers and hoping that its as simple as a new plug and gasket.

 

While I was waiting for parts to come in from the dealer I started looking into what type of gear oil I'll need to refill with.  I learned that this was not cut and dry question as people are going as far as mixing two or three oils together.  I don't have a WRX or STI and I don't currently or plan to ever race anybody.  My question is what is what type of gear oil will work well without damaging anything?

 

So far I've gathered that I need a API GL-5 grade 75W-90 gear oil.  I think I need to stay away from full synthetic and limited slip additives.  I haven't been able to find anything that meets these requirements at my local auto shops.  Right now I'm thinking I'll just see if I can have the dealer sell me something.  Any thoughts?  Again, I just need something that won't damage my transmission.

 

On a similar note, does anyone know if there's a torque spec for that drain plug?

 

 

[Dj7291993]

Pretty much any current 75w90 you find at the part store will meet API GL-5, unless it is really old.  Synthetic won't hurt anything, though it's not needed.  Valvololine works and is stocked by pretty much everyone.

As to the torque, service info says 32.5 ft/lbs for aluminum gasket, 51.6 for copper gasket.  You could probably get away with just the gasket, but the plug won't hurt.  You'll want a T70 bit to take it off, though.

[1 Lucky Texan]

name brand non-synth GL-5 should be fine. Also, the Subaru Extra-S or w'ever it's called now, should be available in quarts now.

if you want a single fluid 'upgrade', these all have a following. Motul 300, Amsoil Severe gear or Redline Lightweight Shockproof.

there's an inexpensive 'dark horse' contender that has a following - Walmart SuperTech synth-blend. just over $5 a quart too!

 

Edited February 15, 2017 by 1 Lucky Texan

[zubricki]

Thanks for the torque specs Dj.  I saw that I needed the T70 on another thread, but thanks for the heads up.  The dealer mentioned that the gasket had two part numbers for a split model year, I'm assuming that's where the copper or aluminum come in.  They took the VIN so we should be good to go.

 

Lucky Texan, I'm going to end up just going with the Subaru High Performance Gear Oil.  It was surprisingly difficult to find a non-synthetic gear oil without a limited slip additive.  For $10/quart it seems like a good way to go here. 

 

Hopefully the parts come in on time for Wednesday and I can get it buttoned up and back on the road!

[Fairtax4me]

The Subaru HP stuff is good.

Not as good as Extra-S, but you can't get that stuff anymore anyway.