Since Castrol stopped making the 75w90 HypodC, I went with the 80w90 Castrol HypoidC...

1qt Synchromesh
1qt Lightweight Shockproof
Rest of Castrol Hypoid C 80w90

So far soo good, 1st gear just slips in, i know its going t get only better because I only have about 30 miles on it.

I did as much research as I can on the 80w90. I went to several Subaru dealers and walked into Service Shop and asked the techs, they all said We use Pennziol 80w90 Gear Oil and he showed me the drums of it. So from there I figured 80w90 is fine because the dealer techs use them all the time.

**Big Thumb ups to Uncle Scotty**

EDIT: accidental double post

I used the 80w90 also, but I think you can find the 75w90 HypoyC if you look hard enough.

Shifts smooth so far. Comparable to my last change, which was 100% lightweight shockproof, except cheaper.

nope no more 75w90...Castrol stopped making it from what I am hearing.

i just wonder how that 80w-90 will feel in the winter. my local suby dealer uses 80w-90 mobil and another use 75w-90 valvoline.

...with the viscosity of the shockproof being similar to a 30 weight motor oil.....the overall viscosity of the mix should work just fine unless you live above the arctic circle.....

^yeah i forgot this question was about a mix and not straight 80w-90. seems that some dealers use 80w-90 and others 75w-90. i wonder just wonder if it's done out of cost /supply since 80w-90 is much more available or cause they actually have a reason for it.

bear in mind i live in NH, it goes below zero in the winter time.

seems like all Subaru dealers in my area(5 of them, yes I called all of them)
they all stated that they use the 80w90 Pennzoil for Gear Oils...so that made me feel confident for using HypoyC 80w90




**100 miles Update**...shifting feels alot smoother in every gear, checked fluid today, its blue now

thanks Uncle Scotty

what brands and product are you using for the synchromesh and LW shockproof. Don't know much about tranny oil, but i'm at 34k and I think I need to change it again before winter. thanks


chris

edit: and where do you get these products? online or pepboys/autozone?

Pennzoil synchromesh 1qt: Autozone
2 Qts Castrol HypoidC 80w90: Pepboys
1qt Redline Lightweight Shockproof: Local SpeedShop

80w-90 will not make cold shift a lot worse in this mix because the syncromesh fluid already thins out the total solution a lot. The mixture is thinner at normal operating temperature compared to a 75w-90/80w-90 gear oil. And it is also thinner at start up, thus will not affect cold shift much (compared to running straight 80w-90).

FWIW - a Subaru mechanic told me to use only 1/4 quart of synchromesh. He said that's all you need to smooth out the shifting and it won't cause excessive wear on the synchros.

At 60K miles I added 1/4 quart of synchromesh and my shifting was smoother, esp into first gear from a roll. My 4th gear synchro died at 90K miles. This is on my '03 WRX with over 320 ft-lbs of torque.

if you can't get castrol 80w-90 or 75w-90, what would be the next best thing to use. penzoil, valvoline ...etc

I used the Valvoline once and didn't like the results....I bought the Costal 75w90(Advance) this time....it usually takes a at least 1k miles to tell if it is good or not....so far it is ok....the Castrol HypoyC worked very well.

I recently changed my tranny fluid (appx 250 miles back) and went with valvoline 75w. It does fine when the tranny get a little warmed up, but when i first start driving, its a nightmare.
Could i add the qt of synchromesh to tranny now? and do you think it would help?
(i know they are bad questions...but i'd appreciate any opinions)

Thanks,
Arvind

I hated the shifting feel (and grinding) after changing to the Valvoline75w90, so drained out a qt of it and added in a qt of synchromesh...shifting was improved, but nowhere as good as the factory fill and still too notchy feeling.

Ended up switching to Swepco 201 (80w90) a couple thousand miles later. Much nicer shifting than the Valvoline...nearly as good as the factory fill IMO, though it is tighter on the first couple shifts on <35F mornings. Think I'll be trying out Scotty's blend (maybe with the Swepco 201) before this Winter kicks in.

Brent.

^makes you wonder what the factory tranny fluid really is. many people seem to believe it is valvoline 75w-90, but i have read other reviews where people used it and it didn't shift as good.

I'm using Valvoline 75W90 (for almost 25K miles now - changed it once between then) and it's working wonderfully. Grinding into first happens maybe a once or twice a month - and that's usually if I don't pay attention and rush it into first. I don't think there will ever be one solution (meaning tranny oil formula) for EVERY member on here. If anything, we've all come to find out that Subaru trannies are that persnickety...