[Riceman]

So short of Motul 300, whats the consensus on the best dino oil to use in the tranny as well as the best oil for LSD. I would like to change out the gear oil in the tranny for sure now that I got a few thousand miles on it I bet I got some metal in the pan after the break-in.

[Singletrack]

Originally Posted by Riceman

So short of Motul 300, whats the consensus on the best dino oil to use in the tranny as well as the best oil for LSD. I would like to change out the gear oil in the tranny for sure now that I got a few thousand miles on it I bet I got some metal in the pan after the break-in.

There was VERY little metal on the tranny plug when I changed the fluid at 30k. The oil also smelled, looked, and felt brand new. I think changing it early is a waste IMHO.

I would change the fluid in the rear diff though. Mine was BLACK and there was a large amount of metal on the drain plug. Just my 2 cents : )

[munky69]

<-- fromer suby tech... we would change the tranny and diff fluids at 30k. honestly every car, STi,wrx,**** any manual suby, the trans fluid looked fine. when i did mine, it looked and smelled new,& like above, i felt it was kinda useless. thought the rear diffs, well that's another story. fluid was always black,including my own. if you drive straight (highway) alot ,then it tends to get dark quicker . i can tell you that no suby dealer carries the diff fluid, or even knows about it. i highly reccommned the suby diff fluid(subaruparts.com),and far as trans/front diffs, it's up to you, but i'm trying out the motul soon as it arrives. i have the **** we used at the dealer in there right now, and damn it sux.(castrol 75w90) shifting is harder,and my rear diff locks up alot more now(not good when one tire is in the air,damn stiff suspension and even parking lots ) i'm surprised no one ever complained after getting a 30k about it. but then again most people that bring their car in for oil changes don't really pay attetnion to stuff like that

[mmahan]

My $.02:
I run Red Line 75W90NS in the tranny/front and 75W90 in the rear. I daily drive, track day and long haul the car quite regularly with no issues what-so-ever.
Have been running this way since I purchased my '04 in July '03.
Have almost 30K miles on her.
As others have mentioned above, the rear diff seems to take the most beating: I swap all fluids after race weekends and the rear is black and smells like hell, while the motor, tranny/front almost seem like a waste to change at that point... but I do them all anyway.

[Rev]

Originally Posted by sciolist

So then 90LS in back and Gear 300 75w90 in front? Is anyone having synchro problems with the Gear 300?

Been running my Gear 300 since the last 23,000 miles more or less. No issues, however, when I first changed it I was having some slight 3rd gear grinding ...

After that, I've been double clutching every time and haven't had any issues.

I'll probably change the gear oil when I hit 8000 more miles... Expensive stuff at $12.50 per quart.

Lately, it's been running great, though. During very cold starts, it shifts very nicely... I would definitely do Gear 300 again.

For the rear I've been using Mobil 1 75W-90. When the fluid gets old, I get some chatter during tight turns. However I've been changing the fluid every 10,000 miles and it's smooth. I'm going to put in the stock Subaru LSD oil next, or the Motul 90PA

[Matt30]

Yeah I have heard problems with synthetic in the trans. I would stick with the dyno oil.

I know that there are some friction additives you can use if your syncros are bad, (GM syncromesh is one that gets alot of press) but be carefull as it's really thin and needs to be put in on top of regular oil.

Wouldn't recomend it for the rear unless you want to feel everytime the clutch packs are working.