Another Transmission Fluid/Rear Diff Fluid Thread

airplnmdls · 09-15-2009, 09:30 AM

Ok...I know there have been like a million other threads about which transmission/rear diff fluid should be used. I have read them all, and I'm still not completely clear on what I should or shouldn't get. From what I get so far is that...keep in mind my car is stock except for stage 1 AP for now...

1) I could get the factory replacement (oem) fluid, which in the service manual says that both the tranny and the rear diff take gl-5 75W90, is this correct? Or is there a different rear fluid?

2) Redline 75W90NS for the tranny and 75W90 for the rear diff...I can get it from their website, but does anyone's local auto parts store or walmart/meijer sell this stuff? Has any one had issues running with this combo?

3)Motul Gear 300 75W90 gear oil all the way around...this stuff is too expensive though, is it really worth it?

4) Go to the local auto parts store and get either Mobil1 or Royal Purple 75W90 Synthetic Gear Oil...now are either of those two choices bad for either the tranny or rear diff? Because I'm running Mobil1 5W30 and filter, and am thinking about making it all the same brand...

Are there any other good reccomended brands that I am missing? Also I'm not a big fan of the whole mixing thing (aka Uncle Scotty's Cocktail, etc...). Is there REALLY a BAD choice? Or do people just like to nit-pick over small noises that really don't mean anything? Any clarification would be a BIG help, thank you!

pzr2874 · 09-15-2009, 12:01 PM

I say stick to the Subaru S fluid for your tranny..... Alot of the mixtures are good for "worn" trannies or upgraded trannies. Try the S.

airplnmdls · 09-15-2009, 01:36 PM

Ok, so the extra S in the tranny and just their regular 75W90 for the rear diff? I found a website called fredbeansparts.com that sells quarts of the extra s...anyone ever buy from them?

pzr2874 · 09-15-2009, 02:00 PM

Chk with your dealer.... MINE told me I can buy it from them, just bring a container. I'm not sure you can order it from many places NOT in a 5Gallon bucket. turninconcepts.com has it too.

airplnmdls · 09-15-2009, 07:03 PM

Well I called my two closest subarus and the first one said he didn't have it but he's heard of it from someone else asking. Then the second one didn't hear of it, then he said he also didn't have it when I asked... :-( And i've looked on TIC and I can't find it on there at all. If you can, can you send me a link? Like I said, fredbeansparts.com has it (I found out they a a dealership in PENN that sells it so I think it's legit) and I think I might buy it on there...5 qts for the tranny and the rear diff...for 12 bucks/quart its not any more expensive that say red line, and i haven't heard any problems with it...

AkSoul · 09-15-2009, 07:40 PM

i've been runnuing royal purple 75w90 in my tranny and diff. for a couple years both work great. I've used Royal Purple in all my other vehicles and i have nothing but good things to say. I used to run the engine oil but its kinda overkill for 3k changes which i do. For my engine I run castrol syntec with a bosch filter. It seems to wear a little les than mobile 1 imho.

pzr2874 · 09-16-2009, 05:54 AM

Quote:

Originally Posted by airplnmdls

Well I called my two closest subarus and the first one said he didn't have it but he's heard of it from someone else asking. Then the second one didn't hear of it, then he said he also didn't have it when I asked... :-( And i've looked on TIC and I can't find it on there at all. If you can, can you send me a link? Like I said, fredbeansparts.com has it (I found out they a a dealership in PENN that sells it so I think it's legit) and I think I might buy it on there...5 qts for the tranny and the rear diff...for 12 bucks/quart its not any more expensive that say red line, and i haven't heard any problems with it...

Wellllll, TiC is just selling Motul right now.... slackers.

Go w/Fredbeans... 12.00 per qt is not all that bad for something that only needs changing every 25-30K.

I'm just suprised the dealers out there don't sell it like the one down here. It's a dealer for krist sake.... What do they put in their customers cars when they need service?

airplnmdls · 09-16-2009, 06:06 AM

Before I talked to those two dealer's parts counters I asked for their service departments...the first one says they just use 75W90 all the way around, and the second place told me they just use penzoil that you can get at your local auto parts store!!!

pzr2874 · 09-17-2009, 02:10 PM

That's a crock..... Order the S.

/thread

man show · 09-17-2009, 07:14 PM

I'm gonna go ahead and vote for Redline 75W-90 NS in the trans and Redline 75W-90 in the rear diff. I can't find it anywhere locally near me. I just look for the cheapest place I can find it online, but I've had no problems with it in my 07 WRX so far. I started using it at 3,000 miles after my break-in period and then again at 30,000 miles. It's easy enough to do yourself, so I'd avoid having a dealership do it because, like you said, they probably don't really care what goes in it and you'll probably save yourself a couple bucks and have the satisfaction of knowing you're using a good product.

Also, fyi, there's been evidence saying that Uncle Scotty's Cocktail is actually chemically harmful to your gears, so you might want to avoid that one. I haven't heard any bad news about the Andrewtech Cocktail if you want to try that.

c2bcoolwrx · 09-19-2009, 12:12 PM

+1 avoid USC like the plague, Blackstone oil analysis proves it turns acidic over time (after approx 10K miles).

I have tried Subaru Extra S, Redline 75w90NS, and Motul Gear 300 in my tranny. All are good, but my favorite has been the Motul Gear 300 as it is clearly the best/smoothest shifting for me. For the diff I have always used Redline 75w90, but next time I will probably get an extra Bottle of Motul Gear 300 for the diff.

However, the key for a smooth shifting tranmission is regular oil change intervals. Subaru recommends to change every 30K miles, however I have noticed that most oils start to show their age (shifting is not quite as smooth) after about 20-25K miles. So I tend to change my tranny fuild about every 25K miles.

pzr2874 · 09-21-2009, 05:59 AM

My dealer is charging me 8.23 per quart..... They HAVE to have it there. Maybe spring for a 5 gallon drum and sell it to guys on here to make more than your money back. I'm considering doin that myself.