Diffs and 6MT oil change

[strongstuff]

Hi all, hoping someone can help please.

 

I have a 2012 Legacy 2.0D SE and I'd like to change the oil in the 2 diffs and also in the transmission.

 

Has anyone seen a guide to do this?

 

I'll need to know quantities and grades of oils too please. (I don't have the owners manual)

 

I'd really appreciate any help.

 

Thanks!

[FLlegacy]

If you have the 6mt gearbox I believe it is 5 quarts in the trans/front diff they are in the same casing, so changing the gearbox oil changes the diff. The rear is just under a quart.

 

I don't know the conversion to liters offhand but that should get you started. Any GL-5 rated 75w-90 will do, but motul 300 is well reviewed in these cars.

[SpidermanMTL]

I used 5 liters to do the trans and the rear diff.

[cww516]

Same here- bought 5 1L bottles to do both, and I have a splash left in the bottom of the last bottle.

[A_A_ron]

I recently had a new (to me) transmission put in due to the reverse gear problem. In doing my research on the forum I ended up deciding to go with BG Sychromesh and I loved it. I gave me some of the smoothest shifts I've ever felt.

 

Jace2010LGT made the recommendation in this thread. There is also some detail on the factory recommendation for oil type, weight, and amount as well.

 

http://legacygt.com/forums/showthread.php/perhaps-better-6mt-fluid-260872.html?highlight=6mt+oil

[thegiraffe]

Does anyone else have trouble shifting into 1st with the LGT 6MT when the car is moving and also with the 1 -2 shift? All other shifts seem fine but those two "moves" feel very forced. It seems to only like to go into first if I am at a dead stop which has been really frustrating. I am also wondering if there is a wear in period sinse the transmission was just rebuilt and its only been a couple hundred miles and I am just impatient / not a fantastic manual driver. I am in a colder climate so their has potential for a very big temp swing and I have been trying to double cltuch to help with the smothness.

 

I have fresh Subaru High Performance 75W90 in the transmission (not extra-s) and I was thinking about switching to Motul 300 75W90 as a first attempt at the concern?

 

Does anyone have any recommendations or similar expiernces with the LGT 6MT transmission?

 

Edit: Well I overlooked the link and tired to find all of the information I could on this.

 

Is this still the recommend fluid setup for the 6MT?

 

I was actually running 3:1. And I'd go 100%,actually, or mix with Redline 75w90NS instead of the Motul 300.

 

Currently I am 100% Redline 75W90NS ("non-slip") which is a GL5 ester-based gear oil without the friction modifiers that normally go in GL5s, specifically designed for transaxles (Such as Subaru and Porche) where the same oil has to lubricate the front differential hypoid gears AND simultaneously allow the synchros the grab. My understanding is that Motul 300 doesn't excel in that second arena, though I haven't directly compared it, so thats anecdotal.

 

 

https://www.redlineoil.com/product.aspx?product=58304

 

In comparison to the 3:1 LWSP/Motul-300 mix, I would say that this is slightly less good at synchro engagement in 2nd when cold, but otherwise similar and far far far superior to the factory fill.

 

Poor synchro engagement causing difficult shifts in low temperatures is caused by high fluid viscosity at those temperatures, while poor synchro engagement/grinding when hot is caused by friction modifiers or worn out synchros. The LWSP excels here because the base fluid is like a 30 weight oil, but it effectively has suspended moly grease in it giving it the shockloading (think - hard shifts) protection of a 140 weight gear oil.

 

While cold, I find that I routinely have to double clutch with rev matching to get it into 2nd while down shifting. However it seems easier to engage 2nd coming fom 4th rather than 3rd. 1st engages easier than 2nd, so I am guessing that there is a fluid-flow design flaw in these transmissions around the 2nd gear synchros.

Edited March 4, 2018 by thegiraffe

[Shadow_419]

Does anyone else have trouble shifting into 1st with the LGT 6MT when the car is moving and also with the 1 -2 shift? All other shifts seem fine but those two "moves" feel very forced. It seems to only like to go into first if I am at a dead stop which has been really frustrating. I am also wondering if there is a wear in period sinse the transmission was just rebuilt and its only been a couple hundred miles and I am just impatient / not a fantastic manual driver. I am in a colder climate so their has potential for a very big temp swing and I have been trying to double cltuch to help with the smothness.

 

I have fresh Subaru High Performance 75W90 in the transmission (not extra-s) and I was thinking about switching to Motul 300 75W90 as a first attempt at the concern?

 

Does anyone have any recommendations or similar expiernces with the LGT 6MT transmission?

 

Edit: Well I overlooked the link and tired to find all of the information I could on this.

 

Is this still the recommend fluid setup for the 6MT?

 

 

Shifting into 1st while moving really shouldn't be done anyway, but it's rough to get in unless you're nearly at a stop. Think it's pretty normal from what I've read. 1st to 2nd can be notchy for me at times but more when the transmission is cold. 3rd to 2nd is the one that can be a pain unless double clutching sometimes.

 

I use AMS Oil Severe gear 75W90 for the record. I'm about 20k miles into it since I drained and filled when I first got my car. Overall I've been pretty happy with the gear oil. A little thick when the temperature drops into the teens or lower but still shifts and warms up quick enough.

Edited March 4, 2018 by Shadow_419

[cww516]

3>2 is hit or miss until it warms up, 2>1 is basically a no-go unless I double clutch (and with as bad as I am at that, I'm basically stopped by the time I get it in gear). 1>2 is usually fine, though. MotulGear 300, probably 23k or so on the oil by now.

[apexi]

Does anyone else have trouble shifting into 1st with the LGT 6MT when the car is moving and also with the 1 -2 shift? All other shifts seem fine but those two "moves" feel very forced. It seems to only like to go into first if I am at a dead stop which has been really frustrating. I am also wondering if there is a wear in period sinse the transmission was just rebuilt and its only been a couple hundred miles and I am just impatient / not a fantastic manual driver. I am in a colder climate so their has potential for a very big temp swing and I have been trying to double cltuch to help with the smothness.

 

I have fresh Subaru High Performance 75W90 in the transmission (not extra-s) and I was thinking about switching to Motul 300 75W90 as a first attempt at the concern?

 

Does anyone have any recommendations or similar expiernces with the LGT 6MT transmission?

 

Edit: Well I overlooked the link and tired to find all of the information I could on this.

 

Is this still the recommend fluid setup for the 6MT?

 

I wouldn't replace the fluid, would just be a waste of money and good fluid in my eyes. I think shifting into 1st while moving will probably always be difficult, and not the fluids fault.

 

I don't have the 6MT, but I love red line 75w-90ns which was mentioned earlier. I've also run amsoil severe gear 75w-90 which is a good fluid too, but the red line is my top pick.

[FLlegacy]

I have extra-s probably closing in on a change soon, I get some rough changes when cold but I take my time and just nudge it. Going back to first almost never happens, lol. So you are not alone. I would probably go for the extra mt or motul first then go for the redline if that doesn't do it. Or you know whichever is easier to get for you.

 

I have a few dealers for redline and motul near me so I will probably go with the motul on the next change. The extra-s is pretty good once warm though. I think it has been discontinued.

[thegiraffe]

I have extra-s probably closing in on a change soon, I get some rough changes when cold but I take my time and just nudge it. Going back to first almost never happens, lol. So you are not alone. I would probably go for the extra mt or motul first then go for the redline if that doesn't do it. Or you know whichever is easier to get for you.

 

I have a few dealers for redline and motul near me so I will probably go with the motul on the next change. The extra-s is pretty good once warm though. I think it has been discontinued.

 

^^ Thanks for this and the other comments. I am definitely not the best manual driver, but its good it know I am not alone with these concerns. As I drive the car more I am sure I will just learn how to work around these.

Edited March 4, 2018 by thegiraffe

[dgoodhue]

Does anyone else have trouble shifting into 1st with the LGT 6MT when the car is moving and also with the 1 -2 shift? All other shifts seem fine but those two "moves" feel very forced. It seems to only like to go into first if I am at a dead stop which has been really frustrating.

 

You really shouldn't be down shifting to 1st all that often, even if your rolling put it in 2nd gear and you can just slip the clutch a little. I have over 90k miles of driving 5th Gen 6MT and I have probably only downed shift to 1st a handful of times over those miles. 1-2 can be stiff when the transmission is cold on a cold day, but once it warms up it should improve. These definitely aren't the smoothest transmissions.

 

Is this still the recommend fluid setup for the 6MT?

 

No the cocktails are not recommended at all. One of the cocktails has been proven to be harmful to the transmission with oil samples and Blackstone (company who does oil samples) doesn't recommend cocktails.

 

I would stick the fluids that Subaru recommends or meets the GL-5 requirement. These transmissions are too expensive and unique to the 5th Gen Legacy GT to be fooling with oil mixes and oil that don't meet Subaru specifications.

[coco26]

I have extra-s probably closing in on a change soon, I get some rough changes when cold but I take my time and just nudge it. Going back to first almost never happens, lol. So you are not alone. I would probably go for the extra mt or motul first then go for the redline if that doesn't do it. Or you know whichever is easier to get for you.

 

I have a few dealers for redline and motul near me so I will probably go with the motul on the next change. The extra-s is pretty good once warm though. I think it has been discontinued.

 

I'm using motul and shift quality is basically the same as the stock fluid that had 50k on it. In cold temps (<15F) I sometimes had to go 1st>3rd because it was so hard to get into 2nd until it warmed up. That being said, I'm probably going to try redline next.

 

I also have the struggles getting into 1st which I'm guessing is just a characteristic of the trans design. 2nd can be hard sometimes, but I've found rev-matching helps a lot.

[Jace2010LGT]

I recently had a new (to me) transmission put in due to the reverse gear problem. In doing my research on the forum I ended up deciding to go with BG Sychromesh and I loved it. I gave me some of the smoothest shifts I've ever felt.

 

Jace2010LGT made the recommendation in this thread. There is also some detail on the factory recommendation for oil type, weight, and amount as well.

 

http://legacygt.com/forums/showthread.php/perhaps-better-6mt-fluid-260872.html?highlight=6mt+oil

 

FINALLY!!!!! Someone else is using BG synchromesh!!! It’s so good in our trans. THANK YOU!!

[abakja1]

I recently did a fluid change front and rear diff for 6mt and the front only took 3 qts.

I took a dipstick reading and its already reading at the high mark,..Rear diff took the 1 qt.

 

I did jack the car up from the front, so is this why only 3qts drained out only?

 

I don’t want to overfill the front diff/6 sp. trans, but i did drain the fluid till it stopped dripping.

 

Am I short on trans fluid or do i add the last quart of motul fluid?

Edited September 25, 2019 by abakja1

[dgoodhue]

I have done 6MT oil change 3 times and each time it has taken ~4 quarts. I would take the car for a spin around the block and check the oil level.

[abakja1]

I have done 6MT oil change 3 times and each time it has taken ~4 quarts. I would take the car for a spin around the block and check the oil level.

 

Its actually been 3 weeks now since doing the fluid change and it still reads at the high level mark with only 3 qts put in.

 

Could jacking up the front of the car up high have anything to do with not draining all of the front diff and trans fluid out on my 11' LGT?

 

Ive done this on my 05' LGT and did not run into this problem of not replacing all the fluid.

[dgoodhue]

Its actually been 3 weeks now since doing the fluid change and it still reads at the high level mark with only 3 qts put in.

 

Could jacking up the front of the car up high have anything to do with not draining all of the front diff and trans fluid out on my 11' LGT?

 

Ive done this on my 05' LGT and did not run into this problem of not replacing all the fluid.

 

Uneven jacking seems reasonable why it only took 3 quarts. I had put my car on jack stands and ramps so it was relatively level to swap the transmission fluid. I refilled it with the car on the garage floor.