Front Diff and Transfer Case Oil Change Howto

Probably the way she was sitting. I get a very small drip from the front usually.

 

Anyone put MT fluid in their transfer case?

MT fluid usually meets GL4, safe for brass and synchros (since there are synchros in manual trans, and I think there are synchros in at least 4H on chain drive t-case),
and can find 75W in MT?

from what I'm seeing viscosity is lower for GL5 75-90 than for GL4 75-90 at 100 and 40 degrees centigrade? an it looks like t-cases and trans call for lower viscosity fluid compared to hypoid? think t-cases have a pump maybe that's why they need lower viscosity?

this is all considering SAE viscosity rating for motor oil is different than gear oil, and SAE 75-85 gear oil can pour just like 5w30 motor oil? right? so the 75Wxx doesn't really mean its thicker than 5wxx motor oil, just different nomenclature for gear and motor oil? When I drained the rear diff, the 75w85 poured out like water. looking at 75w85 viscosity for redline, it's the same as 5w30 so it makes sense.

looks like royal pruple synchromesh is ok for transfers cases but I didn't see any SAE ratings on those so I'd rather not go there.

did see:

Genuine Hyundai Fluid (08950-00020-B) Manual Transmission Fluid - 32 oz.

https://www.amazon.com/Genuine-Hyundai-08950-00020-B-Manual-Transmission/dp/B00BJMLTQ2

But there's also:

https://www.redlineoil.com/product.aspx?pid=45&pcid=7

Wranglers want you to put ATF in their t-cases with automatic trans. When you look up auto trans on mobil site for the type that wrangler specs, the viscosity is very similiar to 75W80 GL4 gear oil, so I could see why wrangler wants ATF in their JK's. The only difference is the flow at 40 degrees is lower but flow at 100 degrees is similiar and viscosity index is a little higher. but don't know that I want to put ATF in the transfer case. although did read on a hilux forum about red ATF looking fluid coming out of the drain on a t-case change. Trying to get hilux service manual is like hell. Figured see what they put in those since lf 75w seems US spec'd.

The GL5 is probably too slippery for t-cases, let alone the sulfur compounds?

So it seems like, MT GL4 75-85 would work?

from what I've seen, toyota lf 75w is 10.cst at 100 centigrade and 120 cst at 40 degrees, with a viscosity index of 185. It's almost the same viscosity index, and flow/kinematic viscosity/"flow" at 100 degrees as redline MT, but lower at 40 deg, so flows better. BUT has the same viscosity index, which I think is how stable the fluid is to viscosity change between cold to hot (40-100)?


This should not be that complex, if toyota just out out the info about their precious 75w LF.

Anyone? I don't mind $50 for something that's going to last many years, I'm just not going to do it out of "F-U" principle to toyota.

 

I used Redline MT90 75W90 GL-4 in the manual 6-speed transmission, and 75W90 GL-5 in the differentials and transfer case.

 

Will this be ok to use for the t-case, manual transmission, front & rear diff?

http://lucasoil.com/products/gear-oil/synthetic-gear-oil/lucas-sae-75w-90-synthetic-gear-oil

It claims that meets both GL-4 and GL-5 and that is suitable for transmissions and differentials, so it meets what the Toyota manual says.

Any comments?

 

I see no claim its GL-4, just GL-5

read this: http://www.widman.biz/uploads/Transaxle_oil.pdf

 

The lucas is similar to this one, on the bottle they claim gl4 and gl5. I guess the question is if is it safe to ise it since it is claiming to meet the gl4.

 

yeah, that article I linked said not to use those hybrid oils in synchromesh manual transmissions.

 

Nissan does the same thing on the Frontier and Titan. Those are notorious for seals going bad, then they leak and folks don't realize it and they run out of fluid and fail.

GM also called for ATF in some AWD transfer cases made by New Process Gear.

 

Just used this for my 2012 and found this kit.

$14 GENUINE TOYOTA GASKET KIT FOR TRANSFER AND DIFFERENTIAL SERVICE

https://www.amazon.com/gp/product/B017V4BAXI/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1

 

I'm getting ready to do this. 80W-90 and

$30 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90 GL4 AMSOil fluids ordered... no luck finding a 24mm hex socket - can someone point out where to obtain from? Lowe's, Sears, Autozone, Advance Auto already checked, as was Amazon (not thoroughly though).

 

I found one at auto zone.

 

For anyone here that has had trouble with the front diff plugs stripping out due to that stupid hex bolt design I have the answer.

I'm sure some of you already know this but instead of using the 10 mm hex socket I used a T-55 torx socket bit, it worked like a charm and only cost a few bucks at Pep Boys. It fits in better and will not strip out the inside of the plug (I had nearly rounded out the inside of the fill plug using the 10 mm hex).

Just thought I'd pass along....

 

Very helpful thread. Thanks

 

So its the same oil for transfer case, front, and rear diff?

 

That's what I plan on using, Amsoil

$30 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90.

 

solid! Thanks man

 

So I know royal purple is the best but can I use cheaper mobil 1 ?

 

I was wondering the same thing...

 

Saw on a few websites that amsoil sever gear is supposed to be the best but its $16.99 a qt and Im a broke guy so Mobil 1?