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Can i use 75w90 for transmission?

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Daaan

15+ Year Contributor
229
0
Aug 15, 2007
Courtice, Ontario_Canada
No store around me sells the specified 75w85 gear oil for my transmition. The dealership says it will take 5-6 business days, and will cost $47 a quart with a minimum order of 3 quarts!(almost $150)WTF
Every performance shop around me has both synthetic and non synthetic 75w90 for $8 a quart. Can i use 75w90 in my transaxle?
thanks for the help
:talon:
 
I'd be looking for royal purple syncromax. I would say see if you can't find a vendor to ship to you up there in Canada. Summitracing carries redline products and I'm sure they ship up there. I'd rather wait a few days than ruin a trans.
 
Probably be fine as long as its GL-4 and not GL-5 but I don't want to be the one to tell you to do it and have you frag your trans.
 
Like stated before, make sure it is safe for yellow metals. Gl4 only.
 
yeah sorry royal purple is GL-5

anything that says "meets requirements for GL3, GL4, GL5" is really just a GL5 gear oil

With 99% of the GL5's you will have long term problems with synchro engagement, because the oil is too slippery
 
I'm currently 'trying" pennzoil synchromesh fluid, via autozone. I'm running an original trans w/212,000 mi. I googled something like "pennzoil synchromesh" or "do I need a new transmission?" and half of first page of the results were direct links to various dsm sites! The consensus seems to be that we don't really need new transmissions, just synchromesh oil. My 93 eclipse has been reluctant to go quietly into the dark night that is second gear since , oh, 1995. When it started bitching about 1st and third, I tried the synchromesh. I think they should have specified that stuff in the first place, even though it probably wasn't around then. The recomendation I read said to change it out at shorter intervals the first few times, every few 1000 miles or so. I think this was just to make sure that the old and new fluids aren't mixed together. I haven't done that yet, but so far all is well, better than ever, and it's been at least 6 months, maybe more, and it's a daily driver.
 
Sorry to threadjack slightly, but you guys are saying that the Royal Purple Max Gear 75W90 rated transmission oil would not be good for an AWD DSM as it says it passes GL5 standards too?
 
that's right...

They're only trying to get you to buy the oil... GL5 is not a standard of quality... it's a level telling you the co-efficient of friction... in other words "too slippery"

GL4 catches the synchros just right and is made for our transmissions. GL5 builds a film and eventually (if not immediately) makes the sychros slip (grinding). GL5 is for RWD transmissions.

You can buy generic GL4 and it will fix the problem just as well as Redline MTL or Pennzoil Synchromesh... You can rarely find it on the shelf, you might have to ask them to look for it on the computer. The only problem with the mineral-based GL4 is that it's full of sulfur and needs constant changing.

I have purchased 2 AWD DSM's that had grinding transmissions... and they both stopped grinding with generic GL4... after knowing what the problem is, I switch over to Redline. I have actually cured several transmssions in the past simply by switching to GL4.

The good thing about using Redline or BG is that they're fully synthetic and never need changing.
 
Thanks for that. Will have to look around. I know the Japanese shops will only sell Japanese oil and that is hugely expensive (at least $25 a quart on average) but will see what I can come up with.

So what is the difference between a GL-4 oil and a GL4-5 oil (and while we're at it, a GL-5 and a GL4-5 oil)?
 
I noticed the same thing after swapping to generic gl-4 as a quick fix to get my wife to work. Go fugure, she drives my holset powered dsm. . . but any way. I didn't change the oil that often, and it started grinding a little again. I pulled the tranny for a clutch swap and in with the new generic oil and the grinding when away. . . So the generic oil needs to be swapped out more? This would explain my situation. . .
 
yeah there's sulfur in the oil, which is very slippery, but there's a counter-acting chemical to the sulfur that also protects it from corroding the gears... the counter-acting chemical wears out quickly, this is why Mitsubishi recommends you change the oil every 10k miles. It's bad to use it (mineral-based GL5 is even worse) because it slowly eats away at your synchros.

I believe the DSM gear oil Mitsubishi sells is a sythetic GL4

EDit: just looked up GL4/5... I'm not sure, but I think it's a GL-5 that's claiming it's rated for both, I know they're using it in some Audi's and some owners say that it's wrong and should be using GL4
 
Spectacular. Done some research and it seems like pretty much the only gear oil we can get here in the whole of Okinawa is GL4 or the GL4-5 Royal Purple stuff I've been using. Guess I'll have to keep on going with that for now:(
 
Spectacular. Done some research and it seems like pretty much the only gear oil we can get here in the whole of Okinawa is GL4 or the GL4-5 Royal Purple stuff I've been using. Guess I'll have to keep on going with that for now:(

Nani Ka osagashi Desuka?

LOL I only know a few phrases... But I can tell you what I would do, if I were there

Japan is filled with FWD cars that require GL-4... try the dealership or autoparts store... You might have a hard time finding something online.

Now, are you saying that you did find the GL4?
 
Nope. Didn't find it. I called Autobacs, which is the main chain of general Auto parts stores and they only had GL-5 rated oils. I have found one place with GL-4 rated oil but it's just under $30 a quart as it's non-Japanese.

The hunt will continue. Don't really want to get crappy oil though just for the sake of it being GL-4.
 
well I'm sure mitsubishi has something.... should cost less (compared to what you pay for stuff LOL) over there

Maybe they don't use the GL ratings? try some FWD toyota/honda oil or just call mitsubishi

also try to find out who sells redline
 
This is what I use:
AMSOIL Synthetic Automatic and Manual Transmission Fluid

Its 75w90 GL-4 ... and full synthetic just like the manual states (though it also states 75W to 85W will be ok as well). Also, Shep recommends it as the "best" solution. Though its $12 a quart. Need 2.1 Quarts for FWD, 2.4 Quarts for AWD + .53 Quarts in Transfer case

Please note for you AWD guys the Differential [rear axle] uses different oil from the transmission. It requires 75W-85W90 GL-5 oil. .95 Quarts in Differential.

GL-4 ONLY in transmission and transfer case.

And Mitsu recommends changing it every 35K miles. Your own usage my change that value.
 
This is what I use:
AMSOIL Synthetic Automatic and Manual Transmission Fluid

Its 75w90 GL-4 ... and full synthetic just like the manual states (though it also states 75W to 85W will be ok as well). Also, Shep recommends it as the "best" solution. Though its $12 a quart. Need 2.1 Quarts for FWD, 2.4 Quarts for AWD + .53 Quarts in Transfer case

Please note for you AWD guys the Differential [rear axle] uses different oil from the transmission. It requires 75W-85W90 GL-5 oil. .95 Quarts in Differential.

GL-4 ONLY in transmission and transfer case.

And Mitsu recommends changing it every 35K miles. Your own usage my change that value.


That's what I'm going to run in the new build!:thumb: I'm a preferred customer!... but it's not made for Automatic transmissions at all
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bojanglesracing let me know that Amsoil makes this ^ stuff (THanks AGAIN!)
it's the one thing I was sure that I would buy from Amsoil, but then, they never used to have GL4 and I was always stuck using Redline... but now they make it and I've switched to Amsoil


Yes GL5 in the back
I know they recommend GL4 in the transfer case, but I can't see how GL5 could hurt it... many people are running it in there.

Okay 35k miles... thanks for correcting that... The manual says to change fully synthetic out every 35k miles? why? You sure they aren't talking about non-synthetic?

One thing to remember is that you shouldn't ever have to change out fully synthetic GL4... they use non-corrosive synthetic friction modifiers. I've lived by this in all my FWD/AWD transmissions... 100k miles plus with no problems
 
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