Pictoral Guide to Changing Transmission and Rear Diff Fluids- 5MT 05+ Legacy GT

[RustyShackleford]

It CAN work and it fit just exactly in, So I guess it would be a 1/2 square thing...

 

Actually, no. A 1/2 square drive does not fit exactly, but it works

for most of us, including me. However, the exact fit is a 13mm

square, slightly larger than 1/2". This has been discussed earlier

in THIS thread, in posts 42-44.

[black318i]

1/2=12.7mm not enough of a difference worth mentioning. Put them up to the Pepsi challenge and see if you can tell the difference.

[spect2k]

I've never done this job yet as I am the one asking the question, but I've been doing some research and I'd be careful recommending using the 1/2" versus the 13mm differential socket. Take a look at this thread - people are rounding their bolts using the 1/2"

 

http://forums.nasioc.com/forums/showthread.php?t=1435930

 

.3mm away from the right tool sounds like it's causing some problems. Maybe it works, maybe not. Maybe it'll work the first time but round it off the 2nd time. I don't know, but I'm leaning toward buying the right tool.

 

http://ultimatetoolco.com/drainplugs.aspx

[black318i]

I just did this like 2 1/2 moths ago and can't see how anyone remotely mechanically inclined could possibly round it out. Sounds like the op in that thread did a lot of his own maintenance. I suspect he was over torquing the plugs when reinstalling.

[DukeTrout]

I noticed that a lot of the bare 1/2" socket wrenches have rounded edges. I used a 1/2" extender with square edges, and I felt completely confident that it would not strip the bolt. It was a good fit.

[spect2k]

I spoke to the Subaru tech today. At the subaru dealer by me, to change the rear diff, they would use the 1/2". Not even they have the 13mm piece. That's all I need to know. (On a side note, they said that they would never jack the car up from the rear differential even though it says it in the manual, but that was his personal preference).

 

This all turned out to be irrelevant for me anyway because apparently the spec b 6mt rear differential is different. I got under the car to look at it and I found this to my surprise!!

 

http://i68.photobucket.com/albums/i35/spect2k/IMG00256-20090824-1824.jpg

 

It works the exact same way, but instead of the 1/2" or 13mm differential bolt, there are these 2 17mm bolts. The bottom is the drain and the top one is the fill bolt, just like on a GT.

 

For the front tranny, there are TWO drain bolts, a T70 Torx bolt and a 14mm bolt. BOTH OF THESE ARE DRAIN BOLTS (torque specs below). I know it was mentioned earlier in the thread, but it needs to be reiterated.

 

For anyone doing this work on a spec B with the 6mt, you should have these numbers because they are different from the 5eat or 5mt...:

 

Front: 4.35 quarts Torque: 50lb/ft on T70 bolt & 31 lb/ft on 14mm bolt

Rear: 1.1 quarts Torque: 36lb/ft

 

Here is another thread that proved useful for much info:

http://forums.nasioc.com/forums/showthread.php?t=964993

[fishbone]

I didn't worry about torque, which I might regret later. I reused the same crush washers and tightened them until I felt them crush a wee bit again.

[bemani]

What length extension do you need for the top bolt in the rear diff?

 

Only ended up doing the transmission a couple of weeks ago. I can't believe I don't have anything that can fit in there.

[itzed]

What length extension do you need for the top bolt in the rear diff?

 

Only ended up doing the transmission a couple of weeks ago. I can't believe I don't have anything that can fit in there.

 

I didn't need any extension for either the top or the bottom. I was able to get the ratchet in there and right on it.

[ClimberDHexMods]

apparently the spec b 6mt rear differential is different

 

That's the point, its the R180, same as the STi. Beefier, stronger though completely unnecessarily. The rest of us have the R160, same as the WRX and others, including a lot of Nissans.

[tingtang]

I will be attempting this as soon as I figure out about this crack in my rear diff case....

[spec.B Dream]

...

For the front tranny, there are TWO drain bolts, a T70 Torx bolt and a 14mm bolt. BOTH OF THESE ARE DRAIN BOLTS (torque specs below). I know it was mentioned earlier in the thread, but it needs to be reiterated.

 

For anyone doing this work on a spec B with the 6mt, you should have these numbers because they are different from the 5eat or 5mt...:

 

Front: 4.35 quarts Torque: 50lb/ft on T70 bolt & 31 lb/ft on 14mm bolt

Rear: 1.1 quarts Torque: 36lb/ft

 

Here is another thread that proved useful for much info:

http://forums.nasioc.com/forums/showthread.php?t=964993

 

I tried searching for info about the spec.B transmission crush washers and couldn't find anything so I did some research. I ended up chatting with Ryan Tomol from Fred Beans about crush washers and got the low down. Post 11 in the linked thread lists two part numbers for the 6mt crush washers:

"Transmission Clutch side washer" 803926070

"Transmission oil pan side washer" 803916080

 

According to Ryan, there are actually 3 part numbers for the spec.B. 803926 is needed no matter the year. The oil pan washer varies by build date:

up to 11/07 - 803916080

after 11/07 - 803918060

 

You can send Fred Beans your VIN and they'll let you know what you need. My conversation with Ryan is below.

 

Ryan Tomol: Hello, How can I help you?

You: I am looking at replacing my transmission fluid with the subaru extra-s fluid. I have an 08 Legacy spec.B. Which crush washers do I need? The STI uses: 803926070 and 803916080. Do I use the same for my 6mt? I know one of the drain bolts is different. T70 vs. 21mm

Ryan Tomol: not sure which one will be diff, lemme get the part #'s for you and match them up with the #'s that you currently have

You: cool. thank you.

Ryan Tomol: trans drain - 803926070

You: ok. from what i've read, there should be one additional drain bolt.

Ryan Tomol: browsing the pics now, suby pics are kinda lacking haha

You: yea...

Ryan Tomol: pro date split (not sure why), do you know the build date?

up to 11/07 - 803916080

after 11/07 - 803918060

You: hmmm. i do not know that

Ryan Tomol: if you have your vin I can find out for you if you'd like

You: don't have that on me right now either. thank you for your help. i'll check on it when i get out to my car and then order the right one. at least we have it narrowed down. also, can i confirm that the 803926070 is correct no matter what year.

Ryan Tomol: yup

[JoeFromPA]

I just did the rear diff today; big thanks to Inigo Montoya.

 

I didn't worry about getting the car level. The top bolt I used a ~8" half-inch drive extension. I then added about a 3 feet cheater pipe onto that and it broke loose without too much hassle.

 

The bottom bolt I just hit the ratchet with my bare hand about 12-15 times and it broke loose just fine.

 

I was surprised the rear diff fluid came out looking like gear lube mixed with milk.

 

New fluid went into without any hassle....used a simple pump and it took about 60 seconds of pumping to get the AMSOIL 75w110 severe gear in there. Bolted it back up, wiped the diff off, and took it for a drive.

 

I'll give it a couple of days to confirm, but I swear my quick 2 minute drive had some nicer shifting. Might just be placebo.

 

Anyway, after leaving the car sit for a few hours I found about a baseball size damp spot under the diff. Not sure if that's just residual stuff dripping off or what, so I put a paper towel there and we'll see. I tightened everything back up good, but there were no crush washers or loc-tite used.

 

Guess we'll see.

[ClimberDHexMods]

I'll give it a couple of days to confirm, but I swear my quick 2 minute drive had some nicer shifting. Might just be placebo.

 

Wondering if a drive train expert could chime in... less rolling resistance I guess would make for smoother shifts, but it seems like this would be a very minor influence on shifting unless something was very wrong before. Would like to know.

[SnarlyMarley]

Just used these instructions and I appreciate all the pics and details. Time to put the T70 away for a few years. PM me if you need to borrow one in Upstate New York...

[93turbo2]

I just did my front and rear today on my 2.5i and this write up made things a snap. It's straight forward and only hard part was finding the t70. I used subaru extra-s in the front and rear and everything feels smooth. Thanks for the DIY with pictures Inigo Montoya!

*edit - my rear diff fluid didn't come out milky colored, i'm guessing because i have a 2.5i and not a gt?

[FPerron]

Just a note that it is much easier to fill the rear diff by removing the spare tire, removing the rubber plug at the bottom of the tire well, and running a hose down to the fill hole. No need for a pump.

[Saul_Good]

Just a note that it is much easier to fill the rear diff by removing the spare tire, removing the rubber plug at the bottom of the tire well, and running a hose down to the fill hole. No need for a pump.

 

That's money, thanks!! I was doing it the hardway.

[Inigo Montoya]

I just did my front and rear today on my 2.5i and this write up made things a snap. It's straight forward and only hard part was finding the t70. I used subaru extra-s in the front and rear and everything feels smooth. Thanks for the DIY with pictures Inigo Montoya!

*edit - my rear diff fluid didn't come out milky colored, i'm guessing because i have a 2.5i and not a gt?

 

Actually I think mine came out milky because I am betting I had a seal fail on one of the axles. I will see what happens, I am coming up on 90K so will have to do this again. Plus I think it is time to change the clutch so I will be having to do the front anyway.

[ehsnils]

Milky indicates water. Not a good sign, but I suspect that you have been driving through deep water for that to happen.

 

A double change of oil should rectify that.

 

Offroaders that drives through mud puddles and other inconvenient stuff often have a compressor that is connected to the differential as in the following picture:

 

http://www.bedug.com/pics/diffair.png

 

The air hose is open and ends below the differential, which means that there will only be a few inches water pillar pressure of air overpressure in the differential and/or gearbox while the car is submerged and none at all while the car is out of the water. The air pump is a cheap electrical one that can be switched on/off with a switch on the dashboard.

 

Cheap and simple solution if you have the habit of partially submerging your car.

[apexi]

Just a note that it is much easier to fill the rear diff by removing the spare tire, removing the rubber plug at the bottom of the tire well, and running a hose down to the fill hole. No need for a pump.

 

Awesome tip, I never thought of that

[fishbone]

*edit - my rear diff fluid didn't come out milky colored, i'm guessing because i have a 2.5i and not a gt?

It is not supposed to look like that. If you're going by the color in the pictures, it's because of the flash.

[spatuality]

I have some RedLine Lightweight Shockproof laying around thats rated for about 75w-140. Any votes on this working well or blowing up the rear diff in an 06LGT 5MT?

[fishbone]

Too thick I think.

[ClimberDHexMods]

I have some RedLine Lightweight Shockproof laying around thats rated for about 75w-140. Any votes on this working well or blowing up the rear diff in an 06LGT 5MT?

 

When warmed up, it is a 140 weight. Problem being you want it to be a 90 weight when warmed up, max (according to the manual). You could run it, but then you could run water or dish soap. No one is stopping you