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Change To Syn Gear Oil Now!

73K views 268 replies 95 participants last post by  markthomas1969 
#1 ·
Lots of people mention the subject, but maybe it needs it's own thread.

Change your gear oil to synthetic as soon as you can. I used Mobil 1. One gentleman (he inspired me) used Redline. It might be better but its hard to find, here.

Keep the car level (no ramps, you can reach the drain) and drain every drop of the old oil. Mine only has a few K miles on it. Since my car is lowered, I needed my skinny son to get at the drain plug. Don't lose the washer!

You'll need a long a$$ funnel. Then dump in that Mobil 1.

I think the owners' manual is wrong in the capacity. It calls for 3.75 quarts. I used 4.

Then go for a drive and be prepared for a seriously dramatic change in your shifting and transmission behavior. It's hard to believe it's the same machine.

Go figure.

:) :)
 
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#2 ·
Russ,

Previously, I have used Amsoil in my transmission in my old Acura GSR. It was better in many ways, but I did notice that there didn't seem to be enough friction for the synchros to function properly. I found that a half and half mixture seemed to be right.

Do your synchros still function with full synthetic?

Bill
 
#11 · (Edited)
I'm sure this has been mentioned, but check out this article:

http://www.cobbtuning.com/tech/gearoil/index.html

I really like my Redline ShockProof Superlite - box and rear diff. We put Lightweight in my buddy's Impreza L yesterday. He says it's great but I haven't tried it yet. For him it fixed some synchro problems he was having.

edit: tried it. he's right. it's great.
 
#13 ·
I was also wondering if synthetic oil of mobil 1 is as good as it used to be considering that they now use "hydrocracking" to produce a "synthetic" base from petrolium. They sued Castrol for doing in the same thing with their "synthetic" oil but Mobil lost the suit, and afterwards also adopted the practice which is MUCH cheaper than producing a true synthetic base (and since the price hasn't changed, they just pocket the difference). the old Mobil 1 was rated for jet engine use...the new one is not. From what I've read, it still a better base than regular oil, but it no longer provides NEARLY the performance it used to (like extended temperature resistence since its now back to being hydrocarbon based rather than graphite) and is really not worth it anymore...and if you change your oil every 3000 miles there is NO noticable difference in wear and performance.
 
#14 ·
russ said:
I think the owners' manual is wrong in the capacity. It calls for 3.75 quarts. I used 4.
:) :)
Sorry I didn't get to this thread sooner, but BE CAREFUL:

Overfilling your tranny or differentials can cause serious problems like blown seals and such. The cases are not meant to be completely full.

An extra 1/4 quart shouldn't hurt anything, but I just wanted to make this point clear to everyone!

-Jim
 
#21 ·
I ran about 700 mi. this weekend. Not a "granny shift" in the bunch.

I don't care what brand it is (I use Mobil 1) my transmission is vastly improved!

Synthetic gear oils are the way to go in the rex. I'm going after ther rear diff, next weekend and expect a similar, if less noticable, improvement.
 
#22 ·
blarg said:
according to an article i read, its good for the diffs, it doesn't offer enough friction for quick shifts in the trans. (make if last for ever if you want to granny-shift though).
Lower friction is one of the primary reasons to switch to a synthetic. Its the friction that creates the higher temperatures in transmissions and differentials that cause component wear.

Yes in a way you are correct, lower temperatures (or low friction) causes CONVENTIONAL gear lubricants to thicken which causes difficult shifting. AMSOIL gear lubes remain fluid even at extremely low temeratures to provide instant lubrication to components at start up in low temperature conditions, and continue to remain fluid providing superior component protection, smooother shifting, and increased fuel economy.

Its the reduced heat that it provides that will give you more consistant shifts.

I really doubt there would be proffesional drag cars, nascar race cars, offroad desert racers, stockcars, so on and so forth.... using AMSOIL gear lube if it didnt provide quick shifting.
Otherwise AMSOIL would market to old women not perfomance vehicle owners.
 
#23 ·
hmm...the article I read said that synchros need a certain amount of friction to work, therefore if you put in an oil that's TOO slippery you'll get a lot of use out of your gearbox, but it makes the synchros less effective, so if you shift hard you're more likely to grind your gears...oh here it is...i found it

http://www.cobbtuning.com/tech/gearoil/index.html
 
#24 ·
I havent personally lab tested this to argue otherwise,

I understand what they are saying, but I really dont hear any kind of eveidence of it, more just, "this lubricant is really slick, that can't be good for the synchro" , not we drove this in a car, and while it shifted really smooth during normal driving conditons, we grinded gears everytime we raced.

quote:
"One common complaint about Subaru manual transmissions are how notchy they feel. A common step taken to help reduce this notchy feeling is to use a better gear oil. But which one do we use? Which one works best? Good questions, unfortunately there's no right answer for everyone"

Hey, if you want a notchy transmission than why switch to synthetic at all, you've already got one. The point of making the switch is to protect and provide increased performance.

AMSOIL isnt magic lube, it still allows friction,
and I highly doubt the people who invented synthetics, would overlook something as simple as friction required to make a synchro function properly.
 
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