Hi all,

I need to do my rear diff oil on my 2007 STi Hawk.
Can anyone suggest the correct torque setting for the drain and the fill plugs? Fill plug looks like I'll need a deep 30mm socket, I can borrow that from someone. Will be using a transfer pump to get the new oil in.

Motul Gear 300 75w90 oil coming soon from Opie, they have a discount code EASTER at the moment for 15% off oils and fluids etc.

It's not the LS version of the oil, just the normal one.

 

 

Thanks Don

Looks like 36.1 lb-ft for both plugs.

I'm confused though as to what type of rear diff I have? I was told today I have the viscous type LSD, but a 2.5 6MT seems to say Torsen on the chart...not viscous?
Hopefully the non LS Motul Gear 300 is the right oil?

 

Ring Alyn at @asperformance 01914103770 but if it was me it would be.
Motul gear 300 ls 75w/90.

 

I was expecting this which is why I added the chart.
Whether or not it's viscous or torsen it is a type T diff which comes with a rear diff thermo switch in the level plug hole, hence the deep socket required.


For oil read the chart again - no mention of LS just straight 75w/90
There is no need for LS additive for most if not all diffs used by Subaru road cars.

Out of interest.........
Below is from the US version MY06-07 workshop manual......



Torsen - Wikipedia

The MY08 UK/European WRX STI Hatch onwards uses Torsen as well ........

 

Further more the actual part listing/description for just the Diff assembly........



If you look through the attached pdf from Rallispec, you will see that many 6MT transmissions listed for MY06 and later use this rear diff assembly

 

Richard as FB tuning was saying use a LS fluid as some have been modded to Ls , and Ls fluid works in both set ups , he put the Ls in my Hatchback , but your call 👍 the twist as I did not know the above until recently I have always used the non Ls in my Fsti and to date no known issues

 

Well, what a shower of sh*t that was. Got a 30mm deep socket from B&Q, took off the rear diffuser, jacked the car up one side to gain a bit more access....

But could not get the fill plug off. Tried soaking deep creep into it, can't use heat as it's got the temp sensor in it / plastic plug.
So mission aborted, didn't want anything to shear off. It would not budge, breaker bar etc. A tad frustrating you could say, but is what it is.

The oil has been in there since 2016 and 52k miles ago.

Possibly would've been easier on a ramp, but it's either way too tight (unlikely) I reckon it's just seized in there.....
Anyone else had a fight with a rear diff fill plug?

Do places usually use impact guns on these? Not sure what to do if it's seized on, worst case replace the rear casing of the diff maybe, but that looks a bit tricky, tucked up and half hidden behind the carrier.

 

Not so much with Subarus but when I worked with Suzuki people would try to take rear axle level plugs on Jimnys out with 3/8" ratchets and the like. They are usually pretty tight and they are 10mm square, not 3/8" st the centre would get chewed up beyond recognition.
Our solution, when the customer agreed to buy a new plug, was to weld an old socket on and take it off with a big bar before it cooled!

Might be an idea to take the car a run 1st. Bit of heat might be enough to persuade it?

 

Good shout, I didn't take it out first as I thought the rear diffs only get a bit warm, worth a go though

 

Works surprisingly well!
Works well with later bolt in wheelbearings too, just be careful taking off hot brake discs!

 

they can be stoopidly tight but never had one totally seized...........