{{Official Trans Fluid Thread}}

[06wrx4me]

hmmm i dont get it, which mix is better?
sorry im a noob
thanks

They both work great thus far. One is just a synthetic formulation for the synthetic fans and the other is a Dino equivalent. They both are a dramatic improvement.

[jaqattack02]

Anyone tried the Extra S from Subaru yet? Rumor a while back was that they use it in one of their race cars. It comes in a big drum from Subaru (5 gallons or something like that) for about $100 bucks. That's what I plan on putting in mine in the near future.

[sch3838]

anyone tried 75w-90 lucas synthetic gear oil?

[jaqattack02]

How about Neo Gear oil? They claim to be used by a number of racing teams. From their website.

Used in F-1, IRL, Champ Car, ALM, NASCAR

Here's the site http://www.neosyntheticoil.com/gear_oil.html

Looks like it's pretty expensive stuff. I found it here for $80 per gallon. http://bakerprecision.com/neocirc.htm

Although that's for the RHD oil, which is designed for racing. I can't find the regular HD oil for sale anywhere.

[SubieStylez]

what do you guys use in the rear diff??

[68sprintb]

i used uncle scotty's cocktail for the trans and Mobil1 75W90 synthetic for the rear differential

[WRXcruiser]

putting in uncle scottys cocktail this week for my 02 tranny (everything ordered from amazon) and i used redline in my rear differential about 4 weeks ago

cant wait for the improvement of USC since my gears have been stubborn lately with the cold weather

[WRXcruiser]

wow!!! USC has done wonders for my 02 tranny...
before: grinding, hesitation accepting gears, forget about reverse unless you roll forward first, drove horrible with the engine cold....i really thought i was going to see the end of my transmission

after: no grinding, no hesitation, smooth between shifts, always takes the gear except 1st sometimes in a roll w/o double clutch (havnt tried w/ double clutching, probably works though), always get in reverse if the engine is warm

transmission feels brand new again...experiencing other problems now as a result of taking my IC off to get to the fill hole next time im using a funnel with a hose connected instead of taking the IC off

[06wrx4me]

wow!!! USC has done wonders for my 02 tranny...
before: grinding, hesitation accepting gears, forget about reverse unless you roll forward first, drove horrible with the engine cold....i really thought i was going to see the end of my transmission

after: no grinding, no hesitation, smooth between shifts, always takes the gear except 1st sometimes in a roll w/o double clutch (havnt tried w/ double clutching, probably works though), always get in reverse if the engine is warm

transmission feels brand new again...experiencing other problems now as a result of taking my IC off to get to the fill hole next time im using a funnel with a hose connected instead of taking the IC off

Yeah I use the double funnel technique.

[Yossarian]

I use BG synchroshift II.


Huge improvement over whatever the factory put in there.

[Pavia]

1) Stock factory fluid: no real issues. Shifted just ok.

2) At 10,570 miles I changed out the rear diff to M1 75w90 and the front/tran to USC (original formula). It's so easy to do these changes, I might just do it again at 20k (lol).

I let it drain on level ground for about 3hrs, but the initial 3.25 qts filled it right to the middle of the dipstick. After a day of driving, it still reads in the middle, so yes... make sure you don't put all 4 qts in.

1 qt Pennzoil Synchromesh (pep bys)
1 qt Redline Lt Wgt Shockproof (amazon)
1.25 qt Castol Hypro C 80w90 (pep bys)
T-70 torx bit (amazon)
Measured funnel w/ hose (pep bys)

The fill order was Syncromesh, Redline Shockproof, and Castrol, with the top-off (.25qt) being Castrol.

The verdict? I notice a very real improvement right away in all gears. Smooth as silk. Maybe say a 50% improvement?

[mikeyphotog]

I've got an '06 2.5i wagon, and never really had a problem with the stock fluid, shifted fine maybe a little "notchy" at times.


I changed my tranny fluid at 35k and put in USC, not because I was having problems shifting but because I'd read that its pretty good for curing "notchyness" so I figured it would be like preventative maintenence. It's holding up fine after 6k, even when I double clutch down to first smooth as butter. Reverse doesn't want to slide in sometimes on the first start, have to let it roll back about and inch then no problem. I'm thinkin of trying just the redline combo next time, maybe at 45k if I have some extra money.

[yo vanilla]

cobb used to have a good fluid type comparison on their website but now i cannot find it. but judging by some of the posts here it would be valuable - for instance some fluids have additives that are easy on your syncros but wear your bearings more, and vice-versa.

so thats to say that if you use a fluid that makes your syncros fly real smooth, you could be doing long term damage to your bearings; couple of people mentioned using race fluid and my first thought is that race cars are meant to perform but are not meant to last any longer than they have to...

[farBeyondDriven]

for instance some fluids have additives that are easy on your syncros but wear your bearings more, and vice-versa.

so thats to say that if you use a fluid that makes your syncros fly real smooth, you could be doing long term damage to your bearings

Interesting. Does anyone know anything more about this?

[walter451]

Hey guys I have an 05 4EAT. Will the USC mixture be right for me? And if it is can you list what is in the mixture.

Thanks