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Gearbox and diff oil

PostPosted: Mon Feb 26, 2007 6:54 am
by FoRcE FeD GT-FOUR
wat type of oil do i use in the gearbox and diff in a st185 gt-four?? is it just a synthetics 75-90 lsd oil??? does it have to be lsd??? synthetic?? any one know for sure?

PostPosted: Mon Feb 26, 2007 7:11 am
by Conan
Use the one that the manual recommends.

PostPosted: Mon Feb 26, 2007 7:18 am
by Denver_whiteST185
from what ive gotten from the MR2 boards is that 75W-90 GL-4 gear oil is the best for our trannies and diffs.

Re: Gearbox and diff oil

PostPosted: Mon Feb 26, 2007 7:24 am
by eddie_gt4
ST185 GT-FOUR wrote:wat type of oil do i use in the gearbox and diff in a st185 gt-four?? is it just a synthetics 75-90 lsd oil??? does it have to be lsd??? synthetic?? any one know for sure?


owner's manual is your best friend :smokes:

Image

PostPosted: Mon Feb 26, 2007 12:26 pm
by T-Trac
Denver_whiteST185 wrote:from what ive gotten from the MR2 boards is that 75W-90 GL-4 gear oil is the best for our trannies and diffs.


If you want smooth shifts and dont mind blowing up your transfer case, go ahead and use GL-4. We need GL-5 protection in our gearboxes because of the transfer case that uses the same fluid. Most GL-5 fluids are meant for differentials and do not offer any protection for our synchros. Ideally you want to use a 75/90 fluid that protects for GL-4 and GL-5 so that you can have synchro and transfer case protection. I've been doing quite a bit of digging around and it seems that Castrol Syntrax Universal would be a good match, but you cant get it in the US, so I just ordered some Silkolene Silktran SYN 5 which seems to fit our application as well. I wont know how well it works till I try it.
Use GL-5 Hypoid Diff Fluid in differential, do not use GL-4 in diff. Might as well just put water in it if you do!!
just my $0.02

PostPosted: Tue Feb 27, 2007 2:54 am
by Denver_whiteST185
T-Trac wrote:
Denver_whiteST185 wrote:from what ive gotten from the MR2 boards is that 75W-90 GL-4 gear oil is the best for our trannies and diffs.


If you want smooth shifts and dont mind blowing up your transfer case, go ahead and use GL-4. We need GL-5 protection in our gearboxes because of the transfer case that uses the same fluid. Most GL-5 fluids are meant for differentials and do not offer any protection for our synchros. Ideally you want to use a 75/90 fluid that protects for GL-4 and GL-5 so that you can have synchro and transfer case protection. I've been doing quite a bit of digging around and it seems that Castrol Syntrax Universal would be a good match, but you cant get it in the US, so I just ordered some Silkolene Silktran SYN 5 which seems to fit our application as well. I wont know how well it works till I try it.
Use GL-5 Hypoid Diff Fluid in differential, do not use GL-4 in diff. Might as well just put water in it if you do!!
just my $0.02


Maybe we should see what Subaru's, Evo's, and the like use???

I really don't know much about gear oil though. im glad you posted cause it gave me some valuable info (since im spending around $1800 total on my drivetrain right now)

PostPosted: Tue Feb 27, 2007 4:31 am
by grip addict
Denver_whiteST185 wrote:
Maybe we should see what Subaru's, Evo's, and the like use???


i know alot of the subie kids use a 50/50 split of valvoline 80-90 and syncromesh. gives em the quick shift of doom and offers... decent protection..

me? just running with 80-90 "durablend"

PostPosted: Tue Feb 27, 2007 5:15 am
by db
grip addict wrote:i know alot of the subie kids use a 50/50 split of valvoline 80-90 and syncromesh. gives em the quick shift of doom and offers... decent protection..


You know what. Maybe we shouldn't use what the Subie guys use, and just see what the Evo guys use. :evil:

PostPosted: Tue Feb 27, 2007 5:17 am
by Denver_whiteST185
db wrote:
grip addict wrote:i know alot of the subie kids use a 50/50 split of valvoline 80-90 and syncromesh. gives em the quick shift of doom and offers... decent protection..


You know what. Maybe we shouldn't use what the Subie guys use, and just see what the Evo guys use. :evil:


Thats great :D . im posting this question on a subie fourm and EvoM to see what people think...

PostPosted: Tue Feb 27, 2007 12:24 pm
by T-Trac
The facts are:

GL-4: (synchromesh, ATF fluid, etc..) It is great for synchros and smooth shifts but does not offer much protection for extreme pressure and special friction characteristics associated woth hypoid diifs (our transfer case). That is why most high power cars here running this fluid shift great but blow up their transfer case.

GL-5: (Most Differential Fluids) It is great for Differential protection, extreme presure, friction modifiers etc.., But it does not offer any synchro protection and some actually eat synchros, as in the chemical base reacts with the synchro material (brass or whatever) and reduces its lifespan. That is why most people running strictly GL-5 have grinding issued, but never a blown transfer case.

Ideally you want the best of both worlds. There are fluids out there that protect for GL-5 and GL-4 to offer us exactly what our trans needs. People who mixing synchromesh and diff fluid are in essence providing protectoion for GL-4 and GL-5, but I dont think this is the best way of doing it. Do the two oils "blend" together or do they separate like oil and water? Do all of the chemicals in the two fluids remain inert or do they react with one another and change chemical composition? :shrug: There are alot of unknowns when mixing two arbitrary fluids.

To each is own, you make the decision
Just my $0.02

PostPosted: Tue Feb 27, 2007 1:04 pm
by gt4tified
Amsoil severe gear is the shit....but @ $15/quart it will stay on the shelf. I've used mobil1 75W-90....okay but not good for the synchros.

Going to Belray Hypoid full 90 body now...

PostPosted: Tue Feb 27, 2007 4:58 pm
by Denver_whiteST185
Heres my two threads.

http://forums.evolutionm.net/showthread.php?t=254045

http://www.awdpirates.net/phpBB2/viewto ... highlight=

the misubishi guys are saying that we should use Redline MT90 GL-4 and diaqueen (mitsubishi oem diff fluid)

http://www.lancershop.com/customer/prod ... t=0&page=1

PostPosted: Tue Feb 27, 2007 6:52 pm
by T-Trac
Denver_whiteST185 wrote:Heres my two threads.

http://forums.evolutionm.net/showthread.php?t=254045

http://www.awdpirates.net/phpBB2/viewto ... highlight=

the misubishi guys are saying that we should use Redline MT90 GL-4 and diaqueen (mitsubishi oem diff fluid)

http://www.lancershop.com/customer/prod ... t=0&page=1


Just by reading the description of the lancer fluid, I can see that their transfer case fluid is separate from their transmission fluid, therefore you should disregard any transmission fluid advice from them because their application is completely different from ours! I dont know how subaru does their drivetrain, but if the transfer case fluid is separate from the transmission fluid, it doesnt matter what they have to say because we have to protect both the transmission and transfer case with one fluid. If I run Rotella oil in my diesel, should you put it in your engine? No, they are different applications that require different types of protection. We can compare our rear diff to theirs and use similar fluids, even though most of ours are not LSD. :( What am I up to? $0.06? :wink:

PostPosted: Tue Mar 06, 2007 5:26 am
by FoRcE FeD GT-FOUR
so it needs to be a gl-5 or higher rated oil am i right? so i can use a gl6 rated oil? also does it have to be LSD? thats wat i want to know. also wats better in the diff? a 80-90 or a monograde oil???

PostPosted: Tue Mar 06, 2007 1:41 pm
by T-Trac
ST185 GT-FOUR wrote:so it needs to be a gl-5 or higher rated oil am i right? so i can use a gl6 rated oil? also does it have to be LSD? thats wat i want to know. also wats better in the diff? a 80-90 or a monograde oil???


Ideally you want a fluid that says that it protects for GL-5 AND GL-4 or mentions transmissions, synchros and differentials in the description with a GL-5 rating. Very few fluids out there say this. I dont know anything about GL-6. I am not sure about the fluid requirements of a torsen diff vs. a LSD, so I am not sure if the fluid has to be LSD rated, but it wouldnt hurt to use one that is just to keep your bases covered. Diff fluid 80-90 or just plain 90 :shrug: I doubt you'd ever notice the difference.