Subaru WRX Forum banner

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.

:) :)
 
See less See more
#27 ·
I guess it depends on technique to a certain extent, but people have experienced shifting problems with different tranny oils. Usually along the lines of too slick for the synchros to work properly. Not everyone, but some.

Cobb's evidence is a lot of experience with Subie trannys. No, that article is not a test article, its a tech article. The thing is, not all synthetic gear oils are the same. They are designed for different tasks. To just have one gear oil for everything, you have to have compromises. That's what the article is about. Some oils are best for the rear end, some for trannys that are routinely shifted very quickly (or the guy doesn't know how to drive!) others are best for the bearings in a tranny. Notice that they didn't say your Amsoil was bad, in fact they said that it was quite excellent. Both of the ones they listed. They just don't recommend it for people who need some friction for the synchros to have there maximum effect. Their conclusion is to try several different oils if you don't like the first one.

For example, my buddy's Impreza L has lousy synchros (or he doesn't know how to drive - not sure which) so he tried Redline 75w90 and it was actually a bit worse. So then he tried Redline Shockproof Lightweight. Problem solved. It shifts beautifully now. Others put the 75w90 in and have no problems at all.
 
#30 ·
I changed the gear oil in my tranny and diff. to Mobil 1 syth. 75w90 this past weekend. The shifting did get a little smoother. I'm going to run it a while with the Mobil and see how it works out.

BTW, I know the tranny is supposed to take 3.7qts. I drained what looked to be at least that much out and refilled with 3.5qts. Now, the dipstick shows overfilled. It is maybe a 1/4 inch above the "Full" mark. Anyone have any suggestions on why it shows overfilled? Also, should I drain some of it out or let it be.

Thanks in advance,

Dale
 
#33 ·
Yeah, it's totally normal for it to read a bit high immediately after filling it. Take it for a short drive to get the oil into all the nooks and crannys, let it settle, then check it. If you didn't drain it warm, you didn't get everything out. No big deal, just that it'll take a bit less to fill it.
 
#34 ·
Well I changed mine last week.

And not good.

I mixed 50/50 between redline 75w90 and 75w90ns

Now I have an issue with grinding when going into 1st from 2nd. Or from Idel. Im dropping the fluid tomorrow and putting in 75w90ns only to see how it goes from there.
 
#36 ·
Me too

Baluchitherium4 said:
I changed the gear oil in my tranny and diff. to Mobil 1 syth. 75w90 this past weekend. The shifting did get a little smoother. I'm going to run it a while with the Mobil and see how it works out.

BTW, I know the tranny is supposed to take 3.7qts. I drained what looked to be at least that much out and refilled with 3.5qts. Now, the dipstick shows overfilled. It is maybe a 1/4 inch above the "Full" mark. Anyone have any suggestions on why it shows overfilled? Also, should I drain some of it out or let it be.

Thanks in advance,

Dale
Actually, I did Royal Purple 75W90. As needed, I drained the OE gear oil warm, with the car level (I even jacked up the rear end for awhile to really get all the dino product out.)

After putting in 3.5 qts., I'm about 1/4" (or less) above the full mark. This is measured cold, and the car has been driven over 200 miles with the RP in. What the heck is up with this? I know I got all the OE oil out, and only put 3.5 qts. in. :confused:

Oh well, I'll siphon some out if needed. It's just bugging me.

Jim

BTW - Trans. is noticeably smoother. So far, so good. I plan on doing the rear diff. with RP as well.
 
#38 ·
rayman481 said:
does anyone know how many quarts of redline racing atf i need for my manual wrx? thanks
Ummmm... you lost me between ATF & Manual WRX.
no you need a GL-5 rated oil...

I just came upon this thread & wonder... Is Mobil lube safe for brass scynro's??? besides having a friction moddier is this stuff safe? I know the bottle says "for all bla bla bla..."
I was just curious.
If I had an doubt I'ld call check the link below... (I already have Redline so I wasn't going to dig into it...)

http://www2.exxonmobil.com/SiteFlow/SuppInfo/Contacts/SF_CT_Lubricants.asp
 
#40 ·
TristineLim wrote:

I've been running Mobil 1 gear oil for the last 5,000 miles or so, and it seems to grind more often when I try to shift into 1st gear going 2-3 mph without double clutching. Hmm I think I'm gonna try Redline next.
I've been getting that, too. I'm not sure it's related to the oil, though.

Has anyone else got this problem, with or without having made the switch?

misterx
 
#43 ·
The Redline synthetic you are looking at is formulated to be used in manual transmissions that specify ATF fluids. An example of this would be the venerable T5 manual transmission found in the late 80's/early 90's pony cars (Camaros and Mustangs).

Our manual transmissions (which include a differential due to the AWD nature of our cars) do not call for ATF.

http://www.redlineoil.com/frames/gearoil.htm
 
#44 ·
I just wanted to bring this thread up again. First I wanted to state that I am using Redline Trans Fluid, and AMSOIL 0w30 Series 2000 Oil in the engine. The car does much better with these lubes. But I have a question. I am thinking about getting Shockproof for my Diffs, but do I need to put any friction modifiers in it so mantain the limited-slip effect?
 
#45 ·
Nope, no friction modifiers needed.
 
#46 ·
Player- a dude on iclub that has been through many trannies sugguested to stay with the stock fluid. Although switching to synthetic would be great for about 2 weeks but then it starts grinding more than before you switched. He just now changed to a different type of oil ( I forgot do a seach ;) ), but he had been running the stock stuff for a while.
 
#47 ·
yeah, took it to the dealer 3 times. Basically their story is that the WRX is based on a rally car, not a strip car. if you slam through the gears like you're drag racing the gears will grind. if you're grinding going INTO first gear, like when you're slowing down, that's normal on ANY manual tranny....haven't had a car yet that DOESN'T do that when you try to shift from too high a speed. the only way to keep it from doing that is double clutch into first gear. the problem is that first gear is to much lower than second that the synchro can't quite keep up as well as the other gear synchros. and as far as the whole synthetic gear oil thing....the Subaru mechanic I go to is VERY good....he works on Subaru's and Porsches...he says that synthetic gear oil makes absolutely no difference whatsoever in the car. the OE Subaru oil is a synthetic blend, and since Mobil switched from graphite base to "hydrockracking" a while back, there's really no difference between it and any other oil. You can' rely on it to be stable for extended service intervals anymore, so you STILL have to change it at the recommended intervals, and if you do that, you may as well use the OE synthetic blend which works just as well and is much cheaper...my Subaru dealer charges $19 for an oil change....that's $10 less than jiffy lube...and as for tranny oil...he said replace it with OE oil every 30K miles and you'll never have any problems....his Legacy has almost 300K on it. I was a huge proponent of synthetic oil for a while....but you know what, I put almost 60K on my car this year...about 30K on mobil1 products and the last 30K on OE oil....I've noticed absolutely no difference whatsoever...except the extra cash in my pocket....in fact enough extra cash to put in those underdrive pulleys I've been eyeing for a while...
 
#48 ·
I've got shockproof in my tranny and it's great. Shifts smooth as silk. But then I never try to "slam" the car through the gears. I shift as quickly as I can, but I don't go overboard trying to just jam it in. With any machine you have to have a little mechanical sympathy.

That stuff about M1 being a fraud because they start with an organic molecule instead of an inorganic one is BS. That's an oversimplification of things by people who don't know what they're talking about. That comes from the "more is better" school of thinking. The new M1 is an advance over the old.
 
#49 ·
Check the Tech Reference thread at the top of this forum for more gear oil info.
 
#50 ·
In general synthetic vs non-syn will get you some increase in efficiency which translates to an increase in MPG.
Synthetics shine when the temp goes up. So if you engine, tranny and diff see high temps like at track environment, then synthetic should help reliability.
BTW, which WRX engine does not see high engine oil temps, especially in summer?
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top