Gear/tranny Oil

[cohen]

The guy at the car parts store said to get a certain type (maybe a 90weight?..I'm not sure) but the Haynes manual said like something different like a 30 or 40 weight, for the rear end. I also want to change the t-case, tranny, and front differential oil, so what kind do I need... :judge:

[yozsi]

for both diffs and t/c use 75w-90 gear oil, for the tranny use dextron 3/ mercon if its an auto, if its a stick use gl-4 transmission fluid. i have used penzoil syncromesh, redline mtl, and mobil one syncro something or another, just make sure its a gl-4 lubricant and not a gl-4/5 lube.

[94extreme]

look in that Haynes book again because i guaranteeeeeeeeeeeeeeee you that it did not say w30.

[TerranoNZ]

look in that Haynes book again because i guaranteeeeeeeeeeeeeeee you that it did not say w30.

Wanna bet

 

The book aslo says to run DEXRONII ATF in the transfer case WTF?

[Guest SuperSon]

You got your tranny, motor and diff oil weight all mixed up. The pic you showed is for your motor oil. You mentioned about a 90W? Thats for your front/rear diff oil.

 

 

Some used gl-4 on their tcase depends on your transmission.I used Dextron III for my auto

 

GL5 for your diffs front and rear 90W and my diff has a sticker that says USE LSD OIL ONLY

[TerranoNZ]

You got your tranny, motor and diff oil weight all mixed up. The pic you showed is for your motor oil. You mentioned about a 90W? Thats for your front/rear diff oil.

Some used gl-4 on their tcase depends on your transmission.I used Dextron III for my auto

 

GL5 for your diffs front and rear 90W and my diff has a sticker that says USE LSD OIL ONLY

The pic is for the "Manual transaxle lubricant viscosity chart" See the above title in the pic

[94extreme]

yeah.. that's miss labeled. those are engine oil weights.

 

and yeah dextron in the tc unless it's an older one (2dr) or you switched like i did.

[TerranoNZ]

yeah.. that's miss labeled. those are engine oil weights.

 

and yeah dextron in the tc unless it's an older one (2dr) or you switched like i did.

Well my bad then......and haynes bad

[mws]

Engineer popping in -

You're all right, but then wrong, and then again, maybe not!

 

But seriously:

Gear oils are rated differently than engine oils. If I recall correctly, the viscosity of a GL 70W80 gear oil is pretty close to that of a 10W30 engine oil. And a 70W75 is just a touch lighter, like a 5W20, and is about the same as most ATF's. Confused yet?

 

You should be.... Why all the different standards, and confusing applications? Well, the standards were developed by different groups at different times for different needs. Add to that the products sold in various countries are sometimes labeled and classified differently. New Zealand seems to be one...

 

Soooo.... the short answer for Mr. Cohen and other '87-89 WD owners purchasing lubes in the US:

Differentials, front and rear: standard GL-5 gear oil, 75W90 is optimal. Easy to get, no need to use anything else. GL-5 is required as you need the high pressure scrub protection on those gears.

 

Manual trans: GL-4, 70W80 seems to be optimal. 75W90 also good at higher temps, but can be sluggish in cold. GL-5 protection is not needed in this trans. Add to this that the fact the sulphur based high pressure modifiers typically (but not always) used in GL-5 lubes are believed to be hard on gear synchros, and GL-5 can actually be bad for trans. So do your own research before using GL-5 in trans.

 

Transfer case: Least demanding application of all. I recommend using the same thing used in the trans for convenience's sake. No hypoid style gears, no synchros, no wildly varying or extreme temps, so just about any thing will be OK. Can safely use ATF or engine oil (in normal applications) if that's all you have. Nissan started using ATF in later TC's, and I have not heard of any internal changes accompanying that change. Heck, canola oil would probably work...

 

So there you go. I use Redline MTL in manual trans and transfer case, Redline 75W90 gear oil in both diffs.

 

Notes:

Redline 75W90 gear oil is compatible with open, locker, OR limited slip diffs.

Edited April 28, 2007 by mws

[88pathoffroad]

Honda manual transmissions use 10-30 engine oil. Just a side note.

[Guest SuperSon]

Thanks for clarifying that Prof.Martin...

[XEcaribe]

after how many miles should you change these fluids?

[mws]

every 25,000 to 200,000 depending on usage and how long you want it to last! Heat is the enemy.

 

Under normal use (some offroading, some high stress), I like to change trans and rear diff every 50-75K. If you're towing, back down to 25K on the trans.

 

The TC and front diff can go much longer as they are usually used only intermittently. I change about every 100K or so just to keep the plugs from freezing up.

[mws]

Honda manual transmissions use 10-30 engine oil. Just a side note.

 

And many BMW's use ATF in their manual transmissions.