Gearbox and diff oil

b00staholic

New member
T-Trac,

You seem to know the most about these fluids that protect for both GL-5 and GL-4.

Can you recommend any specific brands of oil that have this specification?

Thanks.
 

EVcelica

New member
From the redline website:
Redline 75W90 NS

This GL-5-type geal oil doesn't contain the friction modifiers for limited-slip hypoid differentials. This makes the transmission synchronizers come to equal speeds more quickly, allowing faster shifting and much easier low-temperature shifting. Can also be used in racing limited-slip differentials where weak spring design causes too much wheel spin.

Take it for what its worth talks somewhat about synchros.
 

Denver_whiteST185

New member
how about how much fluid i should get? im think i remember that i need 4 quarts for the transmission, but i would think i would need more...
 

EVcelica

New member
I read that it takes 5.5 quarts, but I only put in 5 quarts and it started leaking out the fill hole. I would get 5 and put it in until its full.
 

BriinumsBo

New member
T-Trac":2l9y0fz5 said:
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

how bad is it? The service put GL4 EP80W in both - tranny and differential..
ive driven about 1.5k miles and about 30mins of hard track driving. there are some moaning sounds that i dont prefer, but not that loud.
does it matter synthetic/mineral?
 

Corey

Active member
I tried Redline 75W90 in the Diff, and 75W90NS in my tranny for ~15k km.

I dont have any hard data to show it was good or bad. Shifting was good, but by the time i drained the oil for a motor drop, The car had some 2nd gear issues. It didn't grind unless i upshifted after reving very high, it was just stuburn, especially while downshifting.

I double clutched the whole 15k km. And by the time I dropped the motor, double clutching was the only was to get it from 2nd to 1st in a reasonable amount of time (rather than holding pressure on the shifter waiting for it to pop in)

So, i'm giving Royal Purple a try in my ST205 tranny. Its hella expensive. 22$ retail/L, i got it for 12 :D The bottle says its both GL-4 and GL-5 certified.

I dont know if the degrading performace of the tranny was due to age or the oil. There was only 65k km on the tranny.

Royal Purple also makes Powersteering fluid.
 

Chd

New member
I used Redline 75w90NS since my third gear has some syncro issues. Alot of people said that it would help, and it did.

So i strongly recommend that for all, it aint the cheapest but it's good that's for sure
 

toayoztan

Moderator
Though this is a maintenance issue, I felt it would be good to have it in the drivetrain forum since discussion over what gear oil is good is talked about.

People should find it useful here too.

Let me know if you guys don't agree with this, thanks!

Bryan
 

Nitro_Alltrac

New member
This is from the Royal Purple website:

"Max-Gear is recommended for use in truck, motor home / RV, and automotive front or rear differentials, manual transmissions, and lower gear units of marine engines that specify use of an API GL-5 or GL-4 fluid. All viscosities of Max-Gear are formulated with hypoid friction modifiers necessary for use in clutch or cone type differentials. No additional additives are necessary."

Corey, this is what you are using, right?

I guess the question is will it protect the syncros like a GL-4 oil? They have a manual transmission oil as well. It looks like from the description that it should work for both the transfer and the syncros.
 

Corey

Active member
Yep, im using the Max gear.

Just now filled the tranny with it.

Will have to wait a week or so till the car is running to see how it is. But that will be the first drive with the new tranny, so i have nothing to base it on.

corey
 

BriinumsBo

New member
I put "Motul HD 80w90 GL4/GL5" in my torsen. while the original bottle didnt note this, the sticker in our local language said its for "gearboxes and hypoid transfers and differentials without limited slip"..
should I start worrying about that stupid sticker?
 

Nitro_Alltrac

New member
BriinumsBo":3nmh2oel said:
I put "Motul HD 80w90 GL4/GL5" in my torsen. while the original bottle didnt note this, the sticker in our local language said its for "gearboxes and hypoid transfers and differentials without limited slip"..
should I start worrying about that stupid sticker?

That sticker most likely applies to the clutch type diffs. Those usually require either special oil or an additive for the clutches. I know that GM positraction units are like that.
 

BriinumsBo

New member
Nitro_Alltrac":2fqthslc said:
BriinumsBo":2fqthslc said:
I put "Motul HD 80w90 GL4/GL5" in my torsen. while the original bottle didnt note this, the sticker in our local language said its for "gearboxes and hypoid transfers and differentials without limited slip"..
should I start worrying about that stupid sticker?

That sticker most likely applies to the clutch type diffs. Those usually require either special oil or an additive for the clutches. I know that GM positraction units are like that.

That`s what I thought first - clutch type :) i guess it should be fine with torsen, no problems so far, some noises even might be gone, we`ll see :D
A garage that services rally cars, put in GL4 same for tranny and differential, while rebuilding my engine. The GL4 stuff was pretty thick and foamy after 1500km.
 

Nitro_Alltrac

New member
When I put my torsen in, I just used the regular Mobil 1 synthetic gear only. I've run it for probably 6000 miles or so. Everything is fine. You should be fine.
 

Nitro_Alltrac

New member
I have read quite a few posts about people using the syncromesh fluid in their transmissions. They report good results in making the shifts better. This would make sense as syncromesh is rated as GL-4, I believe. The problem is it doesn't offer the protection that the hypoid gears in the transfer case needs.

The question with the syncromesh has been what kind of affect will it have on the transfer. I haven't really read anything about anyone's long term experience. I have seen where some people have mixed the two (GL-4 and GL-5) but I don't know if it really works. I saw somethings where there were concerns about whether the two were compatiable and if they would stay mixed. I haven't tried it myself so I'm not sure. When I change my tranny fluid, I think I am going to try that Royal Purple which is supposed to work with GL-4 and GL-5. It sounds like that Castrol fluid that is available overseas.
 
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