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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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#177 ·
Retro said:
Are you sure those problems were with NS and not the regular stuff? I catch many people getting confused with NS and the regular version. I actually have the PDF saved that mentions the GL rating of Shockproof.. maybe someone lied or was misinformed. I'll look for it and repost it.
Positive. Lots of complaints of the NS as well as the regular. One of my buddies, however has NS + synchromesh and loves it so that sounds like a decent combination. Protection of synthetic GL-5 fluid...plus synchro friendliness of synchromesh. :)
 
#178 ·
scooby24 said:
Positive. Lots of complaints of the NS as well as the regular. One of my buddies, however has NS + synchromesh and loves it so that sounds like a decent combination. Protection of synthetic GL-5 fluid...plus synchro friendliness of synchromesh. :)
Actually it's no longer a GL-5 once you add the Synchromesh.
 
#179 ·
Retro said:
Are you sure those problems were with NS and not the regular stuff? I catch many people getting confused with NS and the regular version. I actually have the PDF saved that mentions the GL rating of Shockproof.. maybe someone lied or was misinformed. I'll look for it and repost it.

Edit: Found it on the last page where they list all the individual oils http://www.redlineoil.com/whitePaper/18.pdf They list Lightweight and SuperLightweight as being GL-5.
Thanks for the link, but I believe they are refering to their lighweight and superlightweight "normal" gear oils- not their shockproof- which they list right below it- lists no GL rating.

I do know the shockproof works- for warranty issues- don't know if it would be the best choice- looks like a bluish green from a science fiction show :)
 
#180 ·
Retro said:
Actually it's no longer a GL-5 once you add the Synchromesh.

this whole talk about gl-5 eating at (brass)syncro's makes me think that is the problem with our trannys the whole time(the teeth can be explained from people not knowing how to shift right ie alittle clutch slip while launching.)

Wouldnt it still be mostly a gl-5 with some gl-4 addidtive? I think im going to drain a quart of the pensoil and add a quart of synromesh(my pensoil is just the synthetic 75-90w)
 
#181 ·
GIRex said:
this whole talk about gl-5 eating at (brass)syncro's makes me think that is the problem with our trannys the whole time.
Absolutely, positively without a hint of any doubt of any kind, NO! EP oil compatibility is well understood and is not an issue in any transmission rated for GL-5 oil. In fact, most modern transmissions will run on it just fine, rated for it or not. It's mainly a problem with people who try to run a GL-5 oil in their '60's classic car.
 
#182 · (Edited)
I can't believe I read through this whole thread. Two years in the making. Very interesting opinions though! I got a kick out of how about halfway through everyone seemed to take a liking to GM's Syncromesh at balkamp's suggestion. Good deal.

I'm at 12,500 right now, but I think I'll just check the fluid at 15,000 and stick with the stock fluid until about 30,000 unless the stock stuff looks nasty.

So what's the recommendation for the rear diff? Will any synthetic 75W-90 of choice do the job?
 
#183 ·
Darrell said:
I can't believe I read through this whole thread. Two years in the making. Very interesting opinions though! I got a kick out of how about halfway through everyone seemed to take a liking to GM's Syncromesh ad balkamp's suggestion. Good deal.

I'm at 12,500 right now, but I think I'll just check the fluid at 15,000 and stick with the stock fluid until about 30,000 unless the stock stuff looks nasty.

So what's the recommendation for the rear diff? Will any synthetic 75W-90 of choice do the job?
Are there pro's and con's to using a super slippery sythetic in the rear LS? I see these things in the stores that talk about locking up and chatter. I put Shockproof lightweight in my rear differential and it seems ok to me.
 
#184 ·
this is an older thread.. but ive read through here regarding brass synchro's... if the trannies have them, Pennzoil Synchromesh http://www.pennzoil.com/products/gear_oil/syncro_fluid.html worked excellent on my 90 Eclipse GST... im not sure if we are able to run it in our trannies, but i will tell you that cold shifts shift like butter, and overall i felt like i had a brand new transmission..

i think another product thats similar is BG Syncrhoshift.. but ive never used/tested it
 
#189 ·
Retro said:
I put Shockproof lightweight in my rear differential and it seems ok to me.
I've been running Redline Shockproof Lightweight for +40k miles throughout the whole drivetrain....it is excellent, I highly, highly recommend it....no grindage whatsoever, also there was no metal found on the magnet plugs when I changed it out about 5k miles ago.....from the look of the oil it could have ran much longer than 35k miles..
 
#191 ·
just switched over to full synchromesh in the trans and WOW... totally smooth now.. no hesitation what so ever... trans didn't grind before, still doesnt grind now.. i can get into first from second around 10-5mph in that area... doesnt grind and you cant hear the gears as much as before...

next is redline shockproof in the rear... gotta order some :thumbup:
 
#192 ·
Lucas 75W90 synthetic gear oil

Has anyone ever used any Lucas oil products in their transmission? I am going to put Lucas 75W90 synthetic in the trans and diff within the next week or two and post my results up here. My 02 WRX has cold 3rd gear grind, and almost impossible to get into reverse.
 
#193 ·
fluid change?

hey men. i got a 2005 wrx with about 26,000 miles on it. you think its about time to change the transmission fluid yet? tell you the truth...ive never even looked at it? im so bad. if its time to change \, what kind do you guys reccomend? Thanks for the help...
 
#194 ·
I finally got around to putting the Lucas 75W-90 in the transmission and diff, all I can say is it made a considerable difference. There is no more gear whining when decelerating and downshifting, overall shifting between gears is smoother, and getting into reverse gear is a breeze now. I did notice this morning when leaving for work, I still had a little bit of cold 3rd gear grind. I have to say I am satisfied with Lucas' oil. Here is a link to what I purchased:
http://www.lucasoil.com/products/display_products.sd?iid=47&catid=2&loc=show
 
#196 ·
Gear Oil issues

Wow! It's pretty interesting to read all of the opinion, fact, rumor, and myth about our products and their success in the Subaru transaxle. Our customer service man Dave Granquist is right in his reply off of our site--75W90NS is the GL5 oil of the correct weight and the 75W90 is for the rear. That's why it's part of our PowerPack for these cars. Plus, your Subaru dealer can't give you any grief over using fluids that aren't designed for the task.

Someone made a smart point? You have to sit back and think, "Maybe my transmission is the problem?!" These transaxles are quite frail in comparison to the pounding and quick shifts you put on them. The oil is often the last thing people change, usually after they are trying to fix a grinding problem... We think some of the mixed results you guys are seeing with GL4 and GL5 fluids of different weights is based on the particular conidition of your transaxle. Our experience with WRX shows that a mechanically sound transaxle can switch to our fluid and have better shifts, better cold operation, put more power to the ground, and get longer life.

The Cobb guys have a lot of tranny experience, but they are quite wrong in their recommendation on their site--our 75W90NS is NOT the best fluid for a rear differential. Our regular 75W90 has some friction modifiers, but it doesn't get in the way of the non-clutch LSD's operation and the friction modifiers actually help the gears a bit.

The biggest difference between the GL4 and GL5 oils is the amount of EP or extreme pressure additives in the blend. It's not a street spec and a racing spec. The GL5 oils usually used for differentials with a hypoid gear, but like in the case of Subaru, they are often a tranny or transaxle spec.

ShockProof is a unique fluid that works a bit like a liquid grease with a microscopic medium--it works well in some street applications and not in others. If there is a pump, screen, or filter in the mix, it usually isn't the right fluid. Street tuners with a lot of savvy use it, but it's on a trial basis. Admittedly, even those of us with a lot of experience have a tough time tracking which fluid is working better for a LSD at any one time, so it's tough to know when it is hindering the process. Superlight is a 70wt, Lightweight is an 80wt and Heavy is a 90wt and these fluids can be mixed to come up with custom viscocities. We haven't done the same testing with ShockProof on the Subaru transaxle like we've done with the 75W90NS, so it's cool to hear that it is working for some of you.

Hope this helps. You guys have a cool site...

Cameron Evans
Red Line Oil
 
#199 ·
I really want to use this GM Synchromesh stuff that everyone was talking about in this thread BUT....I am a little torn because it is a GL-4 and our transmissions call for a GL-5. I am looking at longevity here, I drive 80 miles a day. Will it hurt the transmission that much to run strictly GL-4??? Could I get away with running a mix of GL-4 & GL-5???
 
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